NikkaDe

hey whats up i have a 95 ls with about 160xxx miles and when i drive the car on the streets its drives perfectly fine but when im doing 70+ if i ease of the gas or take my foot off gas its clunks a lil and jerks but not all the times...

im pretty sure its not the tranny cause no matter how fast if i ease off it clunks but not all the time so im sure its not having to shift right? or could it

my guess is axle? motor mount?tranny mount?

PureDrifter

iTrader: (10)

replace trans mount as it's cheap and easy, then go from there.

NikkaDe

ok will do probably this weekend "if" it doesnt rain

morillest4

i've had the same problem with LS before and only noticed when i was driving at highway speed too. like PD suggested replacing the trans mount helped alot with the problem and its as easy as an oil change to take care of

NikkaDe

ok cool. thanks

NikkaDe

where would it be located ? will i see it when i jack up car or will i be be moving things around? sorry honda guy new to lexus -____- lol

waterdog3

Take the plastic engine cover off. Find the TPS. The plug that connects the TPS was falling off. Push it back on and that will solve the problem. It did mine at least.

NikkaDe

ok ill try that tomorrow since that wont take long but ima still swap tranny mount thanks!

YoshiMan

The majority of 95 LS's have a defect in their ECU that causes the car to jerk when letting off the throttle at speeds above 45. The solution is to get the revised ECU out of a 95 model later in the production cycle. 96 ECUs will not work, it has to be from a 95 specifically.

I have an early 95 that had the exact issue. I just got my new ECU in about a month ago and it solved the issue quite well.

Do a search for "95 throttle jerk" and you will find the info you are looking for.

NikkaDe

thanks for all the input guys! but now my CEL just came on -____- lol

LS400FAN

YoshiMan I think you're spot on, I've been having the exact same problem with my '95 LS, I will follow your advice about the ECU, however it's not an overbearing problem since I've been living with it for the last 100k miles and I know how to ease off the pedal to avoid the "jerk", this is still great info to know, thanks. However now that I think about it, I'm wondering if the jerking will prematurily wear out the timing belt, I did notice several "cracks" in the belt when I had the spark plugs covers off, what's your take on this possibility? Thanks again.

LS400FAN

By the way, the "jerk" is unavoidable when I deactivate the cruise control, arrfff.

YoshiMan

Toyota put out a technical service bulletin addressing the issue in the late 1990s and according to them they found that it would cause no damage to any part of the drivetrain or engine, and that it merely was a comfort thing.

Granted, this was aimed to comfort the customers and who knows how much actual testing they did on it, it seems to me if were to wear anything out it would be something drive-shaft related. I can say that mine had done 157k with the jerky ECU and after switching it over, the driveshaft, transmission, and related parts all still work fine and i cn pretty much guarantee that they are the originals!

Its funny how the new ECU fixes the issue, what mine does now it is holds the RPM steady for a little less than a second after you let off the pedal, which smooths it out entirely.

NikkaDe

so how do u find or how can tell between ecu's which is newer? is there dates stamp on the ecu? lol

YoshiMan

Yes, as a matter of fact, they do! My original crappy ECU was made on October the 12th, 1994:


HOWEVER, that is NOT what you want to go off of, you need to look for the actual part number of the ECU, which can be found on the sticker on the outside of it. This is the same original bad ECU as the one pictured above, the part number is: 89661-50220. If you detach the lower kick panel under the glovebox, you can look up and see which one you have. If yours is a california model, it will have a different part number than this one:


Check out this link:
https://www.clublexus.com/forums/ls4...-ls-400-a.html

And this one, which has the actual listing of the new part numbers for both Federal and California ECUs:
https://www.clublexus.com/forums/ls4...tle-shock.html