95LS400Bob

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.

It seems to be a 95 and 96 "thing" with the ecu's near as I can figure. Seems a lot of guys did have some idling problems with the earlier cars and cleaning throttle body cured it. But seems I didn't find anyone with a Gen 1 that would do this stalling thing after 20 or 30 minutes on the highway. Have to do a road test on this ecu to see if it stalls or not. Then we will know more.

My guess would be this. If the car does the normal fast idle when cold...then tapers down in idle speed...that shows the IAC is working. If you have a 100 to 200 rpm idle all the time...I would look at the IAC valve to be sure it is working. If you are getting normal cold start rpm's, then normal 650 to 700 idle..but later in the day are seeing 100 to 200 rpm....I suspect the ECU. Least that is my opinion so far with these tests.

We live at 4400 ft and can get away with mid grade. But our Lexus on regular has a spark knock when first starting it and a power decrease with regular. Only reason we found that out was the wife put in regular by accident. The computer will lay the timing back if actane is not up to snuff...and mileage result amy suffer enough to offset any savings in fuel cost.

Performing a little test here swapping Ecu's. My 1995 original pcm is a 89661-50231 (california) has been removed and in it's place is a test unit 89661-50221 (49 state ecu) from a member's car. Purpose of this is: 1.) Can a 49 state ecu be put in a Califirnia car with no problems? 2.) Does the 49 state ecu have more power and better throttle response? 3.) Since my car has the stalling after 20 min or more of highway speed....will this Ecu solve that problem. 4.) Are there any noticeable issues regarding shifting, idling and performance with this Ecu over my (suspected bad) Ecu? I installed the 49 state ecu and no check engine light...no obvious problems. I thought the car had more power. I told the wife to take it for a little spin and she said it definately has more power. That's all we know at this point. A few more days of driving and the wife testing(this is her car...I seldom drive it) and then a 120 mile road trip to see if the car stalls. I'll report back.

Long as you went in with your eyes open. Have fun and enjoy your new car!

Mine was transmission and motor mounts. Vibration came in about 45. One thing you might test and it helped us find it. 2 people required. Start the car in park..hood up and you work the throttle cable and have one person feel steering wheel for vibration and watch the seat back. About 1800 rpm (as I remember)....the wife said she could feel vibration through the wheel and the see the seat back vibrating slightly. Then we replaced all 3 mounts....did it again...no vibration anywhere...any rpm. Test drive and vibration gone. To tell you the truth I really thought it was in driveline carrier bearing or driveline alignment. Because you could "drive through the vibration." But it was mounts.

Also I noticed some of these outfits that rebuild ECU's also rebuild mass air flow sensors. Another possibility.

I have had 2 salvage title vehicles. Both were so nice you could not tell what had happened to them. I bought them very cheap. But when I went to sell them.....nobody wanted them. Finally a guy in California that had a body shop bought them for cheap and I am sure he had the idea of clearing those salvage titles. So I speak from experience. If I were to buy a salvage title vehicle...then I would plan to drive it till it was a parts for sale only vehicle. That said and the demand for Lexus used or even reasonable parts :( not so bad. But about $3500 is all I would do....again..planning on "being married" to the vehicle. Other reasons I say that is: I paid $4700 for my 95 with 150,000 miles. There was a 94 immaculate car I passed up for $7500 with 125,000 miles. There was a 93 one owner all service records I could have had for $5000. So I think you should look some more unless you want to marry the car.

Personally, a salvage title would not do it for me. And if you ever sell it your buyer will probably feel the same way. And you'll probably always worry about "how bad was it damaged." You're already concerned now. Just my 2 cents.

This is a thread I started when I did my 95. http://us.lexusownersclub.com/forums/index...765entry73765

You gotta learn to do it all yourself or have a very big bank balance. The parts alone are expensive enough. There are enough people and information here to get you through all of it. Brake pads simple Strut bars is probably where most of noise is coming from. 3 bolts. Haven't had to do the rest.

I've got a good tranny guy here but we are 500 miles apart.

You should have a "302" unless it has been changed. "303" is what you want. And I have some spotted in wrecking yards. I even have a 303 spotted in New York. :D Do you get that occasional "jerk"? Not sure if 96's had as much problem with it.

Seems these cars have fewer transmission problems than most. Or at least by the forum posts. If the converter broke a sprag or pump drive or even if the front pump went out....you still have to do the tranny rebuild as all the junk goes through the tranny. How many miles on the car?

VMF you absolutely called it from the get go. :D The more I dug the more eveident it became that all the problems are ECU related. My car will start up cold about 1400. Then taper down as it warms up to the normal 650 at idle. That shows all is fine. But then at a stoplight...you might notice idling at 400 and that gets you to wondering. Then maybe later you are idling higher. Sometimes you catch the tachometer wavering slightly (engine is hunting for that idle speed). All is no big deal and many probably don't notice. Then maybe you are driving along about 40 to 50 mph and get off the throttle for whatever reason...but just for second. When you step back on the throttle (just as you touch it) you feel this jerk or clunk. Hmm? What was that? So you go try to make it do it again. It doesn't. All is normal. So you disregard it. The you take a trip on the freeway...maybe 60 miles down the road. You take the offramp and stop at the light. You look at the tach and you are idling 200 rpm. But the car is smooth and if it were not for the tach...you wouln't know. Next stoplight you come to...it dies. You don't feel it but you see the lights on the dash all come on. You find neutral and the car starts right back up. Engine idle is the normal 650....smooth and steady...not a flicker on the tach needle. You're glad nobody rear ended you and now you proceed with caution. But now it idles perfect every time. A few miles later..you might notice 500 rpm idle or the tachometer slightly adjusting. And the cycle repeats. It never dies on you till you do a freeway jaunt. The real mystery behind all this was we bought the car in the summer this year. It had a check engine light on but ran smooth as silk. The wife had to drive it back to Reno which was a 500 mile trip in a very unfamiliar car which needed suspension work(clunk real bad in the front end) so I was concerned for her. We stopped many times on the way home and the car never died once. For the life of me....I could not figure out why it never died. Then in the research I found where many 95 owners were actually turning on the a/c when getting off the freeway. That steps up the idle and would keep it from dying. Sure enough...she had the a/c on the whole trip home. :P My wife drives the car but never hits the freeway around here. So the car continues to run. But on the trip to Phoenix with no a/c on...the engine dying starts. Therefore the research hunt. I had even created a device that would keep the car running...was planning on doing a freeway jaunt and doing a roadside test to catch the idle control valve nearly closed (which is what is causing the engine to die). But that is not necessary now as the research paid off and I am convinced it is an ECU problem. One member has offered their old Ecu (49 state) to see if it would work in my California car. I just may try that as a test...just to see if it is compatable with my car. If it is, then I will hunt me a 49 state federal pcm #80661-50224. The research also pointed out one troubling fact....Lexus knew about this. Yet no recall. Those people that have 70,000 miles or close can probably raise a stink at Lexus and get fixed...maybe with little money. But those of us with high mileage and a now a 10 year old car have to bite the bullet. Maybe unless you are an attorney. <_< Update: Courtesy of a fellow member here, I have a 49 state ECU coming to test to see if compatable with my California car. That will be interesting.

I bet I must have found near 20 people who had the problems..came in and made a couple posts and hadn't been heard from again. I contacted some by email and I learned a lot. A lot of peoples cars had the symptoms of all the problems but had trouble describing it. And much was confused by throttle body cleaning which solved a lot of Gen 1 problems but not Gen 2.

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.

Have a Lexus dealer run a report on the car. Oasis I believe it would be called. Also prior smog tests have recorded mileage. I am sure a speedo not that easy to set back as speedometer roll back fraud all manufacturers are aware of. A carfax report may be another way to check.

I have something to add to this thread for the next guy who has his radio lights go out. On a recent trip out of town I started losing the radio lights one by one. Guess their lifetime was up. Since hindsight is 20/20.....I should have replaced every bulb in there while I was in there the first time. So...learn from my mistakes. There are 13 soldered in bulbs. These light the radio and switches. Radio Shack #272-1092 works perfectly as a replacement. For the LED backlight there are 2 larger bulbs. Mine were still working but I wanted new. I ran all over and finally found a substitute bulb. That was Radio shack # 272-1141. They are a slight bit dimmer...but will be hard for you to notice the difference. These are bulbs...not LED's. All bulbs are 12 volt. It's a little tedious soldering in those places but I am no expert at soldering and I made it through it. Be careful with the little green covers on the bulbs. Easy to tear them. Here's a link on how to pull the radio out of a 95. http://carstereohelp.com/stereoremovalLexusLS400str1.htm

Now you have really got my wheels turning. Mine is a 95...yet I see this applys more to 96's. My vin is way earlier than the one listed. Further digging around for pcm info I find the following. These are used pcms in case the dealer won't cooperate. 1995 California pcm#89661-50231 49 state pcm #89661-50220 89661-50221 89661-50224 89661-50234 1996 pcm # 89661-50302 89661-50303 89661-50304 1997 pcm # 89661-50340 89661-50341 So if I don't get cooperation from a dealer or Lexus then a wrecking yard pcm might be the ticket. I believe more and more it is a pcm issue as all else checks out. I'll pull my pcm tomorrow and see which one it is since I have to fix the lights in the radio anyway. Update: After some further digging in the threads here I found someone who tried the new 96 #89661-50303 in his car and got an immediate check engine light. I also did some searching part numbers and found the following: From Park Place Lexus: Latest PCM for a 95 Federal emmisions car is 89661-50224 California is 89661-50235-84 Update Nov 28,2004. I've done about 3 days of searching for info and what I have found is all complied in this thread. I'll make a seperate thread when I get the final info but for now...take a look. http://www.clublexus.com/forums/showthread...threadid=142055

I sure hope it is free. I am sure gonna try it. But I have 151,000 and change so there may be some arguement. I do have to read up on the scan tool. Is a nice unit with a lot of features.

Auto Engenuity software. OBDII. http://autoenginuity.com/ Works pretty good but I haven't played with all of it's features yet.

Has stock air filter. I have a laptop with diagnostic software but no scope.

Won't happen around town. Seems you have to be doing freeway driving for at least 20 minutes. Then it happens. It's just like the idle control valve closes nearly completly and lets no air in. After I knew it was doing it...I kept my foot slightly on the throttle to get through towns. But if I let off completly..it would try to idle near 100 rpm and then die. Start immediately back up and idle normal 600. Trouble with these Lexus cars...you can't feel them idle and the only way you know it quit is all the dash warning lights come on.