I posted a few weeks ago about my car running rough. Well, it was runs rough, particularly under medium to heavy acceleration. It is now idling rough and it is not getting any better.

Here is what I have done:

1) Checked coils- I bought one, changed the passenger side, car ran the same. Took the one I took off and replaced the drivers side...still the same
2) Bought fuel additive- no considerable different noted.
2) Replaced the fuel filter (thought maybe something was clogging it, especially under acceleration)

Next up, I am going to replace the ECU with a used one. I have had my thoughts about it for some time as randomly it will shift hard, espcially from park to Drive. Also, randomly the shifting goes wacky. I read that sometimes that can also mean that the ECU is going out.

This isn't getting any better, actually slowly getting worse, so before I get caught somewhere, I'm going to get a rebuilt ECU.

It seems to be plug and play in changing it out.

Thoughts?

 

you can always open the ecu up and have a look. usually when they have symptoms like that it will be pretty easy to spot the problem. sounds like an ecu issue although could be mechanical like an injector but I would start with inspecting the ecu since its a 1992 and the ecu is a known problem with age or certain conditions etc..

 

I checked the ECU and even opened it up. It says rebuilt on the cover but inside looks clean. Ill post some pictures in a bit.

Having said that, my footwell has gotten wet in the past with the AC condensate tube getting clogged but it has been some time.

Will the ECU look different if its bad? Has mine already beem rebuilt by Lexus and is that why it is bad again?

Thoughts?

 

I have symptoms like you, and am putting caps in my 1992 ecu tomorrow. The main thing to do is open up the ecu and look at the caps, (little barrel shaped things, you have about 10 of them) if they are brown and say "Nichicon" on them they are probably junk. About 4 of mine have severe corrosion from the caps leaking, you can check for this too. Here is the basic rundown of ECU cap issues.... https://www.clublexus.com/forums/ls4...capacitor.html

 

I easily have atleast half these symptoms, tachometer, not shifting unless in manual, funny shifting, idle, car running good than bad and more.

I have one on the way, ill post after i install it.

 

yeah anytime that area has gotten wet the ecu is gonna be iffy. also if its due to wetness and not age, it might not just be the capacitors, but other components on the ecu itself = might be toast. usually the caps go with age but water/humidity can speed that up also.