My 95z w90K has run great until last fall. When the car starts, it's responsive, But after 10 minutes and the car is warm, it bogs down to about 2100RPM. After that, it's fine. No power off the line. I can't even pass a Prius. I took it to the dealer twice, no codes, nothing, They dont want to see it anymore

I've seen this issue in other post, but no resolution

Thanks

 

If you only notice the problem after the car is warm, that sounds like an oxygen sensor problem. The car is in "open loop" on initial startup until the sensors are heated. In closed loop they are used to give feedback to the computer to determine how much fuel to give the car. When you go wide open throttle, their input is ignored in favor of a richer mixture, making it run better again. Try replacing them first and see if your problem goes away since they are cheap. And do it yourself if possible...dont let a dealer gouge you 500 bucks to do a simple job. Actually I believe you can force the car to run in open loop and that will give you an idea if they are bad..not sure but its either by unplugging the o2's at the connector or unplugging the MAF sensor...maybe someone else here can advise on that.

 

i am having a similar problem that is progressing getting worse. Also look into the ignition parts cutting out when they get warm. The ICM and coil both could a problem when they get hot.

matt

 

DO NOT BUY AUTZONE BOSCH O2's

only but acdelco! unless you really like changing o2's

 

If it were strictly an O2 problem, disconnecting them temporarily would make the problem go away. Try it.

 

thanks everone, I'll give it a try