95/96 Ls400 Low Idle, Engine Dies And Jerking Thre

[95LS400Bob]

Here's the latest. When I changed the ECU to the 49 state dealio...we drove the car over the exact same ground where it died and it was fine. Thought we got it.

Then we made a trip to Phoenix and low and behold...she dies. Only now..for some reason...instead of dying after 60 mile jaunts...you have to go about 100 miles. Strange indeed.

A few months ago we went to California...a 150 mile trip one way. Never died. Same deal on the way home. Never died.

Since the car runs flawless in every other way I just never got around to doing the $99 rebuild on the ECU. What I would like to have is the new ECU...the one I feel Lexus did to solve the problem. That is the 89661-50224. But I don't want to pay $1000 for it.

Since this is the wifes around town car anyway we are living with it. Someday I might find the new ECU in a wrecking yard with some luck.

So I think I still have the "dies after the highway cruise problem." Gas prices what they were we didn't do any long highway drives.

Once in a while..I get the check engine light. About once a year. And that always turns out to be the P0 420 code. I simply read the code with my diagnostic tool and erase it. The car passes all smog checks and reads 000 on all smog checks. I've looked at both cats and they are clear. Not going to throw money at as many others have chased this P0 code and replaced 02's and cats and still get the code from time to time.

So we drive her on.

It's the "why" that always puzzles me.

[95LS400Bob]

If you watch the tach carefully and catch it...you'll find that yes...the idle goes way low...and then any load (such as turning he steering wheel) and the motor dies. This says to me the idle air control is closed or near closed. The question is "What closed that idle control valve and why?"

The IAC is a pulse motor. It has to be pulsed a lot of time by the ECU to near close position. I had my IAC apart and tried to duplicate the closing on the bench. You would not believe how many pulses it took to get the motor to close the valve even one turn.

We don't know how the ecu is programmed. But for some reason that IAC gets closed.

Only way a guy could prove this (IAC is closed) would be to let the car do it's thing and die. Then without even touching the key..get out and remove the IAC and look at it's position. I suspect it would be closed as the ECU commanded it to do so (for whatever reason). Then when the key is cycled...the ECU resests the IAC back open...and all is normal again. Only to repeat down the road.

If mine died in town I would catch it. But it always dies in some lonely town in the dark when all you want to do is get where you are going.

I even came up with a throttle control solenoid I rigged up...I could turn that solenoid on and hold the throttle open just a tad to keep the engine running till I coudl get somewhere to pull that IAC off and check it's position.

But the car never died. Figures. LOL>

I'll catch it someday.

[prix]

Sorry to hear you still have that engine quitting problem, although the 49 state ECU appears to have helped somewhat. But you've really gone after it in a methodical way, so if anyone is going to solve it, it'll likely be you, not Lexus!

I tried to intentionally make the car die today, and almost suceeded. In park, sat on the the street and fiddled with the AC, turning it off and on at various settings. I did notice that sometimes the RPMs DROPPED when I turned the AC on, going from say 650 to 400 or lower, then it would 'catch it' and idle back up to normal, or slightly higher. But most of the time the RPMs ramped right up when I turned on the AC. They would go from 650 up to 800-1000 with the AC on. Turning it off was always the same, a big drop to 200-400, and then the idle recovers and whips back into the 500-600 range. However, near the end of my experiement, it was dipping down to 100-200 and almost dying. It still recovered, but I think if I'd turned the wheel, based on what you said, it would have died. In fact, I am going to try doing that later today (turning the wheel on the same test). So at least I am getting somewhere in terms of the 'pattern' so am way ahead of where I was a few weeks ago on this. I have also noticed that the car gets harder to steer when I am running the AC (someone on another post told me to check if that was the case, and sure enough, steering gets more difficult with the AC on).

I think I have enough info to call up the mechanic and have him go to work...cleaning throttle and the IAC. And checking the latter to make sure it's working properly. If not, then I'd replace the IAC first, before considering a rebuild of the ECU. Sounds to me like you are saying it could be either the IAC or the ECU that is faulty (causing the problem), right? Either the ECU is doing something it should not do to close the IAC, or the IAC is not working right...

Also, agreed that after the car dies, it does feel like something 'resets'. What you are saying is that the IAC valve is open again? So is this why the steering all of a sudden becomes light and easy? Didn't realize it would have that much of an effect. After the car konks out, and I restart it, the difference in steering is like night and day.

The mechanic was saying the stiff steering could be caused by a faulty solenoid, which under any other circumstances might be a good guess, but I just don't think that's the case. Another reason I don't think it is the solenoid is because I had this same problem off and on BEFORE I had the new power system installed. I thought the new PS system would take care it but it most certainly did not (I had leaks, so had to replace the PS in any case). So it if were a solenoid problem, both the solenoid in the original rack and the replacement rack would have to be faulty. Doesn't seem likely.

I will keep my fingers crossed on the next try at solving this. Will check back here to see if anything has been added before heading off to the mechanic. Can't thank everyone enough!!

If you watch the tach carefully and catch it...you'll find that yes...the idle goes way low...and then any load (such as turning he steering wheel) and the motor dies. This says to me the idle air control is closed or near closed. The question is "What closed that idle control valve and why?"

The IAC is a pulse motor. It has to be pulsed a lot of time by the ECU to near close position. I had my IAC apart and tried to duplicate the closing on the bench. You would not believe how many pulses it took to get the motor to close the valve even one turn.

We don't know how the ecu is programmed. But for some reason that IAC gets closed.

Only way a guy could prove this (IAC is closed) would be to let the car do it's thing and die. Then without even touching the key..get out and remove the IAC and look at it's position. I suspect it would be closed as the ECU commanded it to do so (for whatever reason). Then when the key is cycled...the ECU resests the IAC back open...and all is normal again. Only to repeat down the road.

If mine died in town I would catch it. But it always dies in some lonely town in the dark when all you want to do is get where you are going.

I even came up with a throttle control solenoid I rigged up...I could turn that solenoid on and hold the throttle open just a tad to keep the engine running till I coudl get somewhere to pull that IAC off and check it's position.

But the car never died. Figures. LOL>

I'll catch it someday.

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[yoichisoma]

Sorry for the delay,

I have been out of my mind at work. My LS's original symptoms were exactly as described by 95LS400Bob. Off throttle shock aroud 45, and freeway off ramp stall after long drive with perfect restart performance. I got Car and Truck E. rebuild and Cleaned throttle body. I have since made at least 10 160 mile drives from Redding to S.F. or Sacramento and have never ever had to worry about idle again. I used to have a 90 LS. I think the 95 is quirky because of the attempt to make it fuel efficient. The transmission has strange shift points that is counter intuitive. It shifts up too soon. Anyway, Seems like from some of the threads Lexus will pay for the job if you nag them enough. I also think it is a major safety and liability problem.

Yo.

Hi,

I have a 1995 LS400 with 105k mi. I had the dying engine after long freeway driving.  I sent ECU to Car and Truck Electronics which did not solve the problem.  I cleaned the throttle body completely by taking it off the vehicle.  I have since not had any low idle or dying.  The lowest it will go is 550 which is within the 600 plus or minus 50 which is the "normal" per the Lexus Repair Manual.  at partial throttle and sudden release of throttle, the engine is abrupt.  this is my new issue and I feel that there is a vacuum leak somewhere.

Yo

←

I have one question. When your Lexus would die after the long freeway drive....would it restart immediately and the problem go away till the next freeway drive? I cannot see how restarting the car would solve the issue..even temporarily....if it were a dirty throttle body.

But if your answer is yes...I am more than willing to pull the throttle body off and clean it

←

[cardona6569]

I am trying to make a thread here for the many of those with low idle, engine quits after an extended highway cruise when coming to a stop, and a mysterious drivetrain jerk when you let off the throttle and get back on....sometimes...and usually happening over 40 mph.

My 95 Ls400 built april of 95 which now has 150,000 miles has these problems.

I've done full diagnostics. I've gone after the throttle body and the Idle control valve. All of which were working perfectly. After 3 days of reading threads at several different forums of similar problems with 95's, several emails and follow ups on who found what the problem was and how solved I wanted to put all the information here so the next guy could find it easier.

Some guys are driving around with the a/c on to keep the engine running at a faster idle to keep the car from dying.

I'm convinced all 3 problems are related to the ECM and it's controlling of the idle air control. While there were a couple of TSB's on this it was never a recall. Those of us who bought used or have high miles are out of luck for any dealer help...at least I would think.

Your Ecm is located behind the glovebox on the passenger side. If you want to read what number Ecm you have..you can do that by not removing it. Just remove the lower plastic panel below the glovebox and look up in there. You'll see "Engine Computer Label" and the numbers.

For 1995's:

Your original Ecm is either:

89661-50220 or 89661-50221 if Federal (49 state). Lexus new replacement on the TSB says to replace with 89661-50224

If California then your orginal Ecm is either 89661-50230 or 89661-50231. The TSB calls for 89661-50234

But searching a local Lexus parts site shows that number has been replaced with 89661-50235-85.

The cost of these Ecm's new is just total crazy. But there might be another solution.

One member bought a used pcm from a wrecking yard #80661-50224. He paid about $150 for it and it solved his issues. I did some searching in wrecking yards and there are some of these #'s out there.

If you have a California car then there seems to be few out there. Mine is a California car. I don't know if a 49 state Ecm will work...I suspect it will...but unknown at this time.

Another member bought a remanufactured Ecm for his 49 state car. He paid $300. for it and it has a 1 year warranty. He also stated that it cured all problems. The company he purchased it from was Auto & Truck Electronics in West Palm beach, Florida. He said the part number was #95 Int 56834. (That was a 49 state unit).

There are other places on the web where rebuilt Ecu's are sold. The problem is most are listed by the old number. We have no way of knowing if the old units are rebuilt and then "reflashed" to the later specs which we are looking for to solve these issues.

I'll try to find out about that and post here what I find out.

For 1996's: The Ecm you want is 89661-50303. Original's were 89661-50302. A wrecking yard buddy did a nationwide search and there are used 89661-50303's out there. Evidently these work in all 50 state cars.

Ps: A 1996 Ecm will not work in a 95. It turns the check engine light on. That's been tried.

Update: I just received an email from the gentleman who bought the remanufactured pcm from Auto & Truck Electronics(mentioned above). He confirmed with them that the Ecu had the latest software upgrade before he bought the Ecu. He also commented the car shifted smoother than it ever did.

This info I found concerning the trouble spots such as Idle Problems of the 95 lexus and others.

http://auto.consumerguide.com/Auto/Used/re...iewreliability/

1995-2000 Lexus LS 400: Reliability

Trouble Spots

Consumer Guide's® Auto Editors have scoured repair bulletins and questioned mechanics to search for commonly occurring problems for a particular vehicle. In some cases we also give possible manufacturer-suggested solutions. In many instances these trouble spots are Technical Service Bulletins posted by the manufacturer, however, we have our own expert looking at additional vehicle problems.

Check-engine light: The check-engine light may come on because of a problem with the fuel vapor emissions system. (1995-00)

Dashboard lights: Due to a problem in the printed circuit, outside temperature reading may report -22F. Removing the fuse for 30 seconds should reset the system. (1995-96)

Engine misfire: Undercoating on the oxygen sensor may reduce its effectiveness and cause the check-engine light to glow. (1995-97)

Engine misfire: Rough engine performance above 40 mph can be remedied by replacing the engine-control computer, cruise-control module, and spark plugs. (1995)

[jess]

I need the phone or web address of the Ebay guy who redoes the EMCs. Anyone have that? Thanks very much.

[LS400jockey]

My ls400 95 (144000 mile) is right now at the Lexus dealer with this issue, this is the second dealership that will be looking at it.  The first did not fix it because they could not reproduce it.

I drive it on the freeway every day.

When I drive it for a distance greater than 30 minutes, speeds over 65, brake at a right turning off ramp, idle goes down and it stalls.  The car immediately starts back up.  Drives fine on the city streets, no more stalling after restarting the car.

I get the "off throttle shock" as well.  Thanks for giving me something to try.

←

My cars ECU part number is 89661-50233. The dealer was able to reproduce the stall probem twice in 2 drives by letting a mechanic drive it home. He lives 60 miles from the dealer Their fix for the problem was to clean the throttle body and the IAC. So far this seems to have resolved the problem as he drove it home twice after the cleaning and the problem did not repeat. So far I have not driven it far enough to confirm it does not happen to me, I'll do that soon.

Its now May

I have not experience any of the symptoms since the service last November

[mann777]

Bob thanks for the details information, i want to ask all 1 Gen owners, do you'll have the similar experience. I should say as explained by Bob on a cold start my car revs upto 1100 for max 3 mts and then reduces to 650rpm as steady, even at signals stops and move. Now with the AC on there is a slight increase upto 750-800 on the RPM needle. Now lately i have experienced these jerks during the course of the travel, but never has the engine shown any signs of dying. I have done the TPS adjustments, but the transmission shifts stilll give a slight jerk.

My question to all who are in this forum is it because there is slow death coming to the ECU or is the front and rear bushings need replacement.It will really valuable to share for the 1 GEN owners as well.

Now to Bob I believe if the engine starts to stall after accelration pedal is depressed or after released 4 items are supposed to be checked (1) Idle speed control valve circuit Code 31 in G (2) Airflow Meter Circuit (3) Throttle position Sensor circuit code 47 in G & Airflow Meter Circuit. The following codes are the ones generate, Code 31, Code 71 in G. The above failures are generally cause from the ECM. Now the ECU reprogramming are done by very few ,who promise a lot, but never to funtion on the long run, My collegeau had done the ECU programming by a company name Mitchell Repairs somewhere in CA, i do not have the full details as this was sometime back, he is now positioned in middle east with USAF. But he too had the similar problem, what he mentioned was by the technicians that the above three circuits are reprogrammed, as these were the main culprits for the poor performance and hesitation of the ECT to work on full strength.

[blake918]

Once stalled, it is difficult to start - even after an hour.

The ECU in my '95 was changed in 1997 when the car had only 48k miles. The Service Manager who was giving me my car's service history over the phone today said that the owner brought it in with a complaint of a cold start problem. They ended up tracking the problem to the ECU, and replaced it with the revised ECU--problem solved.

Has anyone else had their ECU cause trouble as early as 2 years and 48,000 miles? That seems rather premature. <_<

[Patric]

Interesting.

My 95 LS400 has High cold idle issues. 1800 to 2000 rpm depending on the ambient outside temperature.

After initial warm up it usually will not go above 16 or 1700 on start up the rest of the day.

The dealer has double checked all the sensors and swears this is normal for a 95 but I've told them it was only around 1400 when I purchased it 7 years ago.

Oh well.

Patric

[93ls400walt]

The factory manual states for on the car checking of the IAC. Listen for a clicking sound from the IAC when the engine is shut off. If no clicking, the unit needs to be removed and checked for mechinical function and electrical specs. Also, I did not read about anyone looking at the DP ( dash pot ) function. in regards to stalling. I beleive this unit buffers the deceleration of the rpm. For a more gradual return to normal idle speed.

[lexusnutt]

I read over at the Club Lexus board that it may be Ignition coils.... seems reasonable to me!

[yoichisoma]

I got my ECU back yesterday afternoon from Auto & Truck in FL so I installed right away. After a short 10 mile trip to verify everythign was working fine I was happy with the upgrade and put the rest of the glove box back in place. A few hours later I had to drive to the airport to pick up my wife and after a 30 mile trip at 70 MPH, I came to the exit and when I got to the stop light the engine idled down to 200 RPM, bounced around just a little and then died - exactly like it used to.

The 'off throttle shock' that causes the jerking when letting off the accelerator seemed less but not completely resolved.

Needless to say, I am disapointed. Including shipping I spent just under $400 and I can't tell that they did anything. I specifically stated that the ECU was functioning and was only being sent in for the software upgrade.

I'll pull the throttle body to be sure I don't have something hung up in there, but I can't reason why that would only be an issue after long highway speeds.

Anyone got any comments? I'm lost now.

I also had my ECU rebuilt at auto and truck electronics. Off throttle shock was considerably better but not totally resolved. Off ramp stalling did not occur for about a year now, but just the other day, it suddenly happened. It has been running around 400 rpm on the off ramps which is somewhat abnormal. I am going to be writing to Lexus to at least give me a break on the 89661-50224 now superceded by 89661-50225. The problem can be dangerous if an unsuspecting driver happens to encounter it in a tight situation.

Yo

[nc211]

I am going to be writing to Lexus to at least give me a break on the 89661-50224 now superceded by 89661-50225. The problem can be dangerous if an unsuspecting driver happens to encounter it in a tight situation.

Yo

Which exactly the reason why in all of the TSB's issued for the car, this is the one that is HIGHLY RECOMMENDED, which in Lexus Corporate Lingo translate into "case by case recall". If you present the fact that this problem has been reported to the national transportation and safety board several times from different people, they will most likely cut you a very good deal. They won't pay for it all, since the car is pretty old, but they will pony up on some. I would contact Corporate first, have them contact your local dealer and instruct them to fix your car. If you go to the dealership first, you'll just have to fight your way up the ladder, which will end up with Lexus Corp anyway calling the shots. It's best to go straight past all the road blocks and right up to the top.

Lexus is fully aware of this problem. Do not accept an answer that sounds anything remotely like "well, it's a user defined glitch" or "let us adjust the TPS first to see what that does". If they start to wiggle their way loose, that's when you hit them with the information about the transportation safety board complaints. If you google the safety board, you should find their website. It takes some digging, but you'll find the complaints filled from other owners who site this exact reason for petitioning an official recall notice to be issued. Infact, you should probably see my complaint I filled two years ago about this. Luckily I had the dealership's 30 day / 3,000 mile warranty to use against them. It took some strong legal language, but they eventually caved and performed the TSB for free.

[jayjw]

I had the same problem with my 94 LS400 for the past 6 or 7 months. It was so bad that sometimes I felt the engine almost stalled. Everytime when I stoped in front of traffic light or stop signs, I couldn't to watch the engine rpm. Sometimes it was below 200.

I did a lot of reserch and study. I believe it was the flawed programming in the ECU. The ECU simply can't handle the situation when the Power Steering Idle Up valve stopped working. Here is what I did. Please read this URL.

http://www.clublexus.com/forums/showthread.php?t=239568

After I did that, the low idle speed problem completely gone. It has been two weeks now, the car runs perfectly. The Idle Speed is right at 650 when the car is idling.

[sonyman]

I wish everyone could have it as "easy" as you did nc211. I was unable to get Lexus to do anything for me, and am still needing to have my ECU changed. If it'd be at all possible, I'd like to see what it did for your LS so I could see what it could do to mine.

Scott

[95 ls400]

Here is an update on my car:

I have a '95 LS that now has ~54k. I had the off throttle shock issue between ~45-50mph, and the stalling issue after about an hour at freeway speed. It was originally a CA car and had a -231 ECU. I purchased a salvage -224 ECU last year, but just got around to getting it installed this week. Here are my observations:

1) The -224 ECU fixed both the off throttle shock issue and the stalling issue.

2) The ECU seems to give the car better throttle response and seems to allow the car to upshift on acceleration more readily.

3) Gas mileage seems unaffected so far.

I didn't get around to fixing it until this week because it is just now getting cold enough in Chicago that the A/C is off for long periods of time. In the summer, having the A/C engaged masked the stalling issue, because the A/C forces my car to idle above stall. But I wish I would have swapped the ECU sooner, because the car feels much more responsive with the updated 49-state ECU. Arlington Lexus in Palatine charged me $180 (1.5 hours) to install the new ECU. It took under an hour, but I let it slide.

I hope this information helps.

[jasonmckinley]

first, thank you "bob" for starting a great thread, and thank you to everyone else who posted responses. this has been valuable information for me- i was ready to throw in the towel and get rid of my car until i found this thread.

i have been a toyota fan for about three years now (i've had a 2000 4 runner and an '02 sequoia). i like toyota products for the same reason everyone else does- they ride great, are safe, and are historically extremely reliable and can be "driven into the ground." i bought a 96 ls about five months ago with 133k miles. i drove the car about 350 miles immediately after purchasing it, drove it all over the highway for a couple of months (i'm a traveling sales rep), and never had a problem. i was delighted with my purchase. i then took my car to a dealership to have the power steering pump, water pump, timing belt, and brakes replaced so i can be essentially worry-free for another 50,000 miles. two weeks after i got the car out of the shop, i took a highway cruise of about 200 miles, and when i got off at the exit, my car stalled. this had never happened and i assumed maybe something the dealership had just done may have caused the stall. the car started right back up and never gave me another problem...until the next highway cruise. here were the things i noticed:

- car mileage- around 140k when this first started happening.

- started in cooler weather (fall in the southeast). i'm only pointing this out because it's odd that i drove the car a ton on the highway through the heat of the summer and never had a problem until the weather changed. i always have the AC on, so my rpm's should have been kept at a higher rate regardless of outside temperature.

- highway drives of 45+ miles at a cruising speed above 60mph (i'm assuming since the speed limit here on the highway is 60-70mph everywhere). extreme low idle but not stalling when i would slow down on shorter trips (around 30-40 miles).

- normally stalled after strain (turning the steering wheel)

- could feel a slight hesitation when taking my foot off the gas at speeds between 45-60 mph. almost felt like the car didn't know which gear to put me in when i released from the gas.

long story short- i took the car to the dealer who couldn't duplicate the problem and it happened again and again. only until i went to google and typed in "ls 400 low idle" did i stumble upon this great thread. i went back to the dealership and asked to speak to a mechanic- he was unaware of the ecu problem and eventually went to his computer, ran a TSIB and found the lexus-issued statement regarding my part # based on my VIN (apparently i have an early 96 ls model with an ecu part # ending in 302). he was astonished and basically told me to just get the part and it certainly should fix my problem. i typed in the new part # (89661-50303) on google and got several results of places selling these ecu's that had been yanked out of other cars (i didn't want to get mine re-programmed, i felt it was more convenient to get a whole new unit instead of waiting on someone to re-program). pricing for this other part # ranged from $300 to $450. i found part number ending in 303 from a junk yard in florida for $300 (the dealership wanted $2,100 for the ecu only) and took it to the dealer and for $85 labor (one hour) my new ecu was installed.

i did my first test run today with the new ecu and could feel the car driving differently- more power, no "jerk" at 45-60mph etc. i did about a 65 mile highway cruise and had no problem when i got off at my exit. i remember how i used to watch the rpms shoot straight down once i hit about 30 mph. this is extremely dangerous, especially if you happen to pass through a busy city and hit traffic after a highway jaunt (this happened to me twice; and i'm happy i knew to watch my rpms, quickly put the car in neutral and restart it while still moving around 30 mph). being unaware of this lexus problem is a big safety hazard and a recall should have been issued. i will be writing a letter to lexus explaining the same thing.

i will be taking about a 600 mile one-way trip for christmas and hope i get the same results. for now, the newer ecu has restored my confidence in toyota engineering. these cars are absolutely unbelievable. classic styling, fully functional (although i hate the cupholders), and the best highway cruising you will find. i have become a lexus-for-lifer because of this car. the symptoms i noted above are basically repeats of other threads, but the thread mostly contains info on the 95 LS, and i have a 96. though i am certainly no mechanic (i didn't even attempt to pull out my old ecu and pop the new one in), for others with a 96 ls experiencing the symptoms i listed above, you should feel confident that a new ecu ending in 303 will fix your problem.

[scotty2hottyoki]

I just replaced my ECM for a 93 ls400 and it cost me $175 + $35 overnight shipping. You just send your ecm/ecu to the place, and they fix it for you if possible and return it. the site is www.autocomputersupply.com they are located in houston, tx. hope this helps

[lenexa'95]

I got my ECU back yesterday afternoon from Auto & Truck in FL so I installed right away. After a short 10 mile trip to verify everythign was working fine I was happy with the upgrade and put the rest of the glove box back in place. A few hours later I had to drive to the airport to pick up my wife and after a 30 mile trip at 70 MPH, I came to the exit and when I got to the stop light the engine idled down to 200 RPM, bounced around just a little and then died - exactly like it used to.

The 'off throttle shock' that causes the jerking when letting off the accelerator seemed less but not completely resolved.

Needless to say, I am disapointed. Including shipping I spent just under $400 and I can't tell that they did anything. I specifically stated that the ECU was functioning and was only being sent in for the software upgrade.

I'll pull the throttle body to be sure I don't have something hung up in there, but I can't reason why that would only be an issue after long highway speeds.

Anyone got any comments? I'm lost now.

I also had my ECU rebuilt at auto and truck electronics. Off throttle shock was considerably better but not totally resolved. Off ramp stalling did not occur for about a year now, but just the other day, it suddenly happened. It has been running around 400 rpm on the off ramps which is somewhat abnormal. I am going to be writing to Lexus to at least give me a break on the 89661-50224 now superceded by 89661-50225. The problem can be dangerous if an unsuspecting driver happens to encounter it in a tight situation.

Yo

[lenexa'95]

I got my ECU back yesterday afternoon from Auto & Truck in FL so I installed right away. After a short 10 mile trip to verify everythign was working fine I was happy with the upgrade and put the rest of the glove box back in place. A few hours later I had to drive to the airport to pick up my wife and after a 30 mile trip at 70 MPH, I came to the exit and when I got to the stop light the engine idled down to 200 RPM, bounced around just a little and then died - exactly like it used to.

The 'off throttle shock' that causes the jerking when letting off the accelerator seemed less but not completely resolved.

Needless to say, I am disapointed. Including shipping I spent just under $400 and I can't tell that they did anything. I specifically stated that the ECU was functioning and was only being sent in for the software upgrade.

I'll pull the throttle body to be sure I don't have something hung up in there, but I can't reason why that would only be an issue after long highway speeds.

Anyone got any comments? I'm lost now.

I also had my ECU rebuilt at auto and truck electronics. Off throttle shock was considerably better but not totally resolved. Off ramp stalling did not occur for about a year now, but just the other day, it suddenly happened. It has been running around 400 rpm on the off ramps which is somewhat abnormal. I am going to be writing to Lexus to at least give me a break on the 89661-50224 now superceded by 89661-50225. The problem can be dangerous if an unsuspecting driver happens to encounter it in a tight situation.

Yo

[lenexa'95]

Did you have any luck with getting Lexus replacing the ECU? If so, what process did you go through?

I got my ECU back yesterday afternoon from Auto & Truck in FL so I installed right away. After a short 10 mile trip to verify everythign was working fine I was happy with the upgrade and put the rest of the glove box back in place. A few hours later I had to drive to the airport to pick up my wife and after a 30 mile trip at 70 MPH, I came to the exit and when I got to the stop light the engine idled down to 200 RPM, bounced around just a little and then died - exactly like it used to.

The 'off throttle shock' that causes the jerking when letting off the accelerator seemed less but not completely resolved.

Needless to say, I am disapointed. Including shipping I spent just under $400 and I can't tell that they did anything. I specifically stated that the ECU was functioning and was only being sent in for the software upgrade.

I'll pull the throttle body to be sure I don't have something hung up in there, but I can't reason why that would only be an issue after long highway speeds.

Anyone got any comments? I'm lost now.

I also had my ECU rebuilt at auto and truck electronics. Off throttle shock was considerably better but not totally resolved. Off ramp stalling did not occur for about a year now, but just the other day, it suddenly happened. It has been running around 400 rpm on the off ramps which is somewhat abnormal. I am going to be writing to Lexus to at least give me a break on the 89661-50224 now superceded by 89661-50225. The problem can be dangerous if an unsuspecting driver happens to encounter it in a tight situation.

Yo

[pearlyLs400]

Here's the results after a 70 mile run at 80 mph non stop.

Be sure to read the entire thread. These are the results of replacing my Calif ecu 89661-50231 with a 49 state ecu 89661-50221.

The car idles 600 rpm..absolute steady..not a waver on the tach. Even after the sustained highway driving (it used to die at idle.) This proves my problem was the ecu.

The car has much better power everywhere from stoplight to stoplight or accelerating on the highway. This shows the Cali ecu's are as suspected...cut back on engine performance.

The jerking that happened when closing the throttle and then getting back on the throttle at around 45 mph has only occured once with the 49 state ecu and it was nowhere near as harsh.

So I will now return this borrowed ecu and hunt down a 49 state unit and install it in my car...or will go for the "improved" ecu if I find one at a reasonable price.

Hope this helps someone in the future.

hEY BOB

Seems like you are the man...around lol. maybe you can help me. i read all over your postings but im a women and sometimes things can be confusing for me. I will try my best to address issues in BOB LINGO....

ISSUE: I have a 1990 Ls400 california car, replaced the engine and now i have issues

MISSION: To see if Bob or anyone else can help me in these issue areas?

PROBLEMS

========================

#1. Since the new engine has been installed : THEN ENIGNE LIGHT STAYS ON

#2. Since the new engine has been installed : WHEN I SHIFT IN DRIVE THE CAR JERKS HARD AND JUMPS INTO GEAR

#3. Since the new engine has been installed: When im at a redlight rpm drops to around 200 causing heavy vibrations

#4. Since the new engine has been installed: When the AC is ON problem #3. Is solved

#5. Since the new engine has been installed: MY QUESSTION CAN A 1990 Califonia enigine be replaced with a 1994 (all other 49 state engine)

Thanks can anyone help me

[pearlyLs400]

hEY BOB

Seems like you are the man...around lol. maybe you can help me. i read all over your postings but im a women and sometimes things can be confusing for me. I will try my best to address issues in BOB LINGO....

ISSUE: I have a 1990 Ls400 california car, replaced the engine and now i have issues

MISSION: To see if Bob or anyone else can help me in these issue areas?

PROBLEMS

========================

#1. Since the new engine has been installed : THEN ENIGNE LIGHT STAYS ON

#2. Since the new engine has been installed : WHEN I SHIFT IN DRIVE THE CAR JERKS HARD AND JUMPS INTO GEAR

#3. Since the new engine has been installed: When im at a redlight rpm drops to around 200 causing heavy vibrations

#4. Since the new engine has been installed: When the AC is ON problem #3. Is solved

#5. Since the new engine has been installed: MY QUESSTION CAN A 1990 Califonia enigine be replaced with a 1994 (all other 49 state engine)

Thanks can anyone help me

[Wes-Lexus]

I just replaced my ECM for a 93 ls400 and it cost me $175 + $35 overnight shipping. You just send your ecm/ecu to the place, and they fix it for you if possible and return it. the site is www.autocomputersupply.com they are located in houston, tx. hope this helps

God Bless you!! I live in houston and should be able to drive my 94 LS400 down there and get it fixed. SWEET!!!