1993 Ls 400 Transmission Or Engine Problem?

[CelicaLexus400]

Hello everyone!

My dad has a 1993 Lexus and we are having some problems with this car under hard acceleration When u cruise normally the car seems fine but when u step on the pedal to try to accelerate the CAR starts moving back and forth and the RPMs from will go up to 3000 rpm and back down to 2500 (up and down) and will struggle to pick up speed. The car seems to hesitate and doesnt want to go.

IS this a engine or trans problem?

We just had a major tune up done, timing belt, spark plugs, and even had the ECU comuter chip swapped out and still has the same problem... Any ideas? I appreciate your help thanks!

will a fuel injection or throtle body clean help?

[jamesholden]

Gearbox oil might be ready for changing if it's never been done although would seem a bit trivial if this is the case.

Has it only started happening since you had the work done?

[GreyBeard]

perhaps if you had the gearbox fluid changed but didn't use the lexus specified product (not a substitute) this might have caused it. apparently the lexus oil will not mix with any other, and it forms a gel stuff that blocks the ports, etc. (there's another topic about it).

otherwise, any one of the miriad sensors could be giving a misleading input to the ECU, which in turn is putting out garbage. GIGO. mine's doing something similar but not so extreme, and they did put substitute oil in the autobox, which has now been changed, but i'll have to do it a couple more times to be sure it's clear.

and any inconsistent running can be laid at the door of a dirty throttle body - there's a really good pictogram of how to do the job yourself; it hardly needs any tools at all.

hope this helps a bit.

[CelicaLexus400]

Hey guys

NO the hesitation was happening now and then thats why we performed the major tune up etc. The car still does it when we step on the gas! The car starts hesitation at around 3000RPM and stuggles to pick up speed.

The car seems to be fine when u drive normally but hesitates when u punch the gas. So u guys think the we should clean the throttle body and change the gear box fluids?

we were going to have the throttle body and fuel system cleaned... any other thoughts? the car has aproximately 90k miles on it