pgupta

Does at 91 octane also. I see some improvement if I click the O/D OFF. How do I check if the knock sensor has gone bad?

This is not a shudder -- as in vibration related. This is engine momentarily loosing rpm and power, causing a jerk, or a sequence of jerks. Happens in park as well as drive. It is like the engine starts choking up whenever there is demand for power during acceleration - especially around 1800 rpm. Once above 2200 rpm, it again runs smooth. The problem is not repeatable and I have not seen any corelation with outside temperature or humidity. It is intermittent - pretty bad one day, no problems the next day. I do see that it becomes worse when I put 89 octane vs 91 octane gas. I am thinking it is either a clogged fuel filter or a bad injector.

Any thing further to report? Still waiting to hear if your problem was fixed and what was the cause.

I have the same problem. 94LS400, 200K miles, last tuneup at 120K. Just cleaned throttle body which fixed the "engine dies after a long drive on the off ramp" problem. Now looking for a fix for the shudder at idle, and occasional shudder/hesitation when accelerating. If you find a solution, please do tell!

when my caps and transistor on the instrument panel went out, the gas gage took for ever to come up some - never made it to full. The empty light would still come on but atleast a gallon too late leaving little room to reach a gas station. (now that I have fixed my gage and know at what level it comes on) I kept track of when I need gas by using the trip gage - set to zero when full - fill after 300 miles. quite likely, you need to fix the caps mentioned in this thread to get back your fuel gage. The E light should come on.

Acura has done quite well with the MDX crossover SUV.

Extreme Sports Sedan - Call it the mid-life crisis car! I have the money - now I need to feel young again! Old BMW strategy.

You mean "Tantalum Caps" ... yes, they are definitely the way to go. Besides replacing the caps, there is also a transistor (TR109) that causes the panel lights to go out / flicker / come back in when warmed up. See the "pinned" post on "replacing burnt out needles on intrument panel" on the forum page.

Quite likely excessive carbon deposit inside the throttle body. Have the throttle body cleaned well so there is good air clearance gap for idle air intake even when valve flap is fully closed . Just went through this myself on my 94 LS400. Enough carbon deposit on the valve disk chokes off the air clearance. So after a long drive when idle control is not opening the valve for you since you are no longer "cold", the engine chokes for air and dies when you take your foot off the accelerator. This should perhaps be covered under your 30 day mechanical warranty. It will only get worse over time as the deposits continue to build up. My 2 cents! Hope it helps.

Here is another post I found on the forum "pro"-changing fuel filter. Since I am having the same hesitation problem occasionally, I am going to give it a shot tonight and report back! There was another long post I read elsewhere on Google about the design - there is some kind of "sock" through which gas is sucked from the tank by the fuel pump which helps leave most of the sediment back in the fuel tank. This seems to be common to all Toyota designs hence the lifetime on fuel filter. QUOTE(AaronKooshball @ Dec 22 2004, 03:48 PM) Thanks for the help guys. I ended up changing the fuel filter (lucky me) and it fixed it. Story is, i drove the car back from the dealership with little to no gas in it. That means i sucked up all the sediments on the bottom of the tank and clogged the filter. i'm running fuel cleaner and fuel injector cleaner through it now to help fix it more. Whhheeewww that scared me.

Interesting - you are the first person to report a problem being fixed after replacing the fuel filter. This is encouraging since the fuel filter is supposed to be a life time item. I am having a similar problem on my LS400 and now I am willing to give this thing a first try. Will report back if it fixes my hesitation problem as well.

I went through my maintennace handbook for a 96 Lexus and did not find any instance upto 150K service for replacing the fuel filter in the factory service recommendations. The pics do indicate the fuel filter is dirty. What I would like to know is whether you had a problem that replacing the fuel filter fixed? Like rough idling or lack of power during acceleration. From what I have read elsewhere, the Toyota EFI fuel system is designed so that the filter can last almost a million miles before clogging to the point that it needs to be replaced. I rather not muck with high pressure fuel lines if I don't have to.

You're the first to have a 94 with all the identical symptoms that I know of. Most guys with earlier models cleaned the throttle body or replaced the idle control and solved the problem. ================== Was waiting for the weather to clear up and attempt the throttle clean up as the first step before hitting at the ECU. I found major carbon deposit on the inside. Using a household oven cleaner, I patiently dissolved all the hardened carbon deposit on the valve disk. Now when the valve disk is fully closed, I can see a nice clean clearance gap for the air to flow through at idle. I suppose this was the reason for the engine dying after a long haul. I notice my cold start idle speed went up slightly - 1100 rpm from 800rpm previously. I tried getting off the ramp with A/C off - no dying this time! Will see if I can keep repeating this test and never fail. My reasoning - there appear to be 3 cables keeping that valve open - cruise control, accelerator and perhaps idle control for cold start. So after a long haul, when getting off the freeway, none of the three cables are pulling on the valve to increase its opening and you need that minute clearance to sustain the air flow for idling the engine. With carbon deposits blocking it, no wonder the engine was choking and dying. Now I need to deal with the hesitation at 45 mpg when accelerating uphill. That obviously has nothing to do with the throttle body cleanup as at 45 mph, the valve disk is open quite a ways.

How about a ditto on my car. Reading your post seems like you are reporting my problem. Just died on me this morning on the same off ramp from the freeway to work - only for the 10th time in the year because I purposely shut off the "AUTO" to kill the A/c and lo and behold I was on the side of the road with my flashers on trying to restart the car. Every bit else is identical - start at 1100+ rpm, settles to 650, dies after a long cruise, jerks at 40/45 or even at idle, hesitation when accelerating but only once in a while. There is no true pattern to the jerks or the hesitation during acceleration - thats what makes it so hard to pinpoint the problem. Here is the odd part in your data chain.... mine is 94LS400. Help me! How do I get to the ECU? any pics to help me out?

vcv10guy -- your posts are extremely helpful. They are eliminating all the things that cost a lot of time/effort and money and won't help with my basic problem as well. I bet its the ECU on my car that is flaking out. The instrument cluster (dashboard) on all early Lexus cars has been notorious for bad transistors and capacitors - specially the electrolytic ones. They just flake out over time. Result - flickering lights, gas gage needle not coming up fully etc. till the cabin heats up. Its too early to tell on the late 90 models if they continued to use the crappy components. Takes about 8+ years for them to flake out. It is unfortunate that Lexus will use crappy electronic components. A 33 cent part results in a $1500 assembly being replaced. I can only hope that they are reading this and switch to tantalum caps on all their future designs. However, on the ECU, it appears that the software flashed in the memory has a problem. Wonder if it is similar to what happened on the Mars rover -- over time it accumulates data and runs out of memory to hold it and then starts goofing up. Next thing I plan to do is disconnect the battery overnight, perhaps over the whole weekend, and see if that resets the ECU. I know that disconnecting the battery for a short time does not do it. ================= Yep I replaced that part already and that didn't help (it was cracked though pretty bad too), and I also replaced the ventilation hose that connects from the front cylinder head to the intake boot (was cracked too). I wish those things solved my problem. Thanks Steviej for the suggestion though. Man the more I think about those threads I read, I wonder if I have a lousy ECU too.

So your car acts like that no matter what the temperature is? - Basically yes .. I will have to wait till next summer to confirm. -------------- Looks like my problem is related to the ECU per the link I just posted for you. I will start there first and will let you know if that works out for me. BTW, also see KCTalker on SC400 forum post: Sc 400 Hesitation...?, Normal at low revs? Looks like the Engine Control Module / Unit or ECU in conjunction with the EGR Valve is acting up.

For what its worth, read the post by 95LS400Bob on LS400 forum titled: 95/96 Ls400 Low Idle, Engine Dies And Jerking Thre Search for the above and see if this describes your problem. Given everything else that you have done on this car, this may be your problem.

I am having the exact same problem on my LS400. If I find the cure, I will post for what its worth realising this is ES300 forum. However, mine started acting up in the peak of summer and has exactly the same symptoms. So, I wouldn't place too much emphasis on the "cold" part.

Thought I'd clarify. Picture is worth a thousand words - however in lieu of one, here are a thousand words! The brake pad = 10mm thick braking material on a metal base about 3 mm thick. One end of the metal base has a rectangular slot into which the wear sensor slips in and is locked in place by a spring clip. The top face of the wear sensor is 2mm above the metal base. So, once your pad lining wears by 8 mm, the pad surface and the wear sensor top face are on the same level, both touching the rotor. As the rotor continues to grind away, now both, eventually the wear sensor "opens" electrically and the dash light () comes on. This is different from the "BRAKE" light which is driven by brake fluid level. Keep track of your mileage after new brake pads - typically 6K miles wears out 1mm of pad. So after 36K miles or so, you should think of changing the brake pad. Again, not all wheels wear out evenly. This is just a guide line. If you replace the pads at 4mm to 3mm remaining, you will never have to replace the wear sensor as it would never touch the rotor and get shaved off. Once the wear sensor has been shaved by the rotor, its too late. The sensor itself costs $40 at the dealer + about $30 labor to install it. Depending on the model, not every wheel has this sensor. On a 96 Lexus, I have seen it on passenger rear but not on the driver side rear. Haven't looked at the front axle yet. You can install new brake pads and not replace the wear sensor and ignore the () light. You can't get rid of the light without changing the sensor. What I don't know is whether you can just strip the wires going to the wear sensor and twist them short to defeat the () light. I think they only need to be replaced if broken or like mbpgawest says, when contact is made and the light comes on. I am pretty sure that there will be ample warning (squealing) before the sensor will make contact and the warning light will come on. I have a broken sensor that I think resulted from the wrong pads being used. The sensor contact seemed like it was heat damaged and crumbled when changing the pads. My 97 has two sensors not four -- one on the front right and one on the rear right. The other sensor disconnected and reconnected easily during the pad change. I don't think they are supposed to be replaced each time you change pads unless you waited too long. ←

As its getting colder, I am having the same issue. With cold weather, heat is turned on inside the car. The car is probably heated using the engine coolant through a forced air to coolant heat exchanger. I noticed a plastic mechanism that probably controls the flow of the coolant to the heat exchanger in towards the cabin is showing a drip leak. It is located just under the passenger side wiper blade mechanism. The drip has eaten into some wiring/hose underneath as well. Anyone has had similar problem? I am going to replace that part for starters. Any suggestions from someone who may have already done this?

I am a big fan of Mobil 1 since 1990 : when I bought my first Toyota PU 2WD. At 250K, its still running. I started with Mobil 1 - since day one, every 3K, then every 5K...then 8K - no major engine trouble. Since then I have added two LS400s. Ironically, the PU oil filter (which costs 1/3rd of LS400) works just fine for the LS400. On the LSs, I started with Mobil One every 5K, then 10K ... now once a year, every 20K or so. Even at 20K the oil flows out the drain with good viscosity than regular motor oil after 1500 miles! But don't follow my example! Just don't loose sleep if you missed the 3K mark with Mobil One! Rumor is that Mobil One tends to eat the crankshaft seals - I did develop a little leak in my Toyota at 200K. Can anybody else opine on this leak issue?

Flickering Dash Lights: (In decreasing order of magnitude cost!) Option 1 - go to the dealer and replace the entire combination meter assy. Option 2 - Have Jim Walker repair your combination meter boards. Option 3 - Pull out the boards and replace components yourself. Visit http://web.ukonline.co.uk/soarertt/blinkidash.htm. TR109(BC639 or equiv) on motherboard and C212(10uF/16V) on daughter board are suspect.