Hi everybody.
I'm a guy from Sweden with a 1989 Iroc Z28.
I just reg.on this site because I have a strange problem with the car.
It starts in 1/10 of a sec. and the idle is smooth and even but after it gets hot the engine runs even if I keep the rpm over 1000, if I release the throttle the rpm goes up and down for around 5 min and then shuts down.
If I start it again within 1 min. it starts fine and the idle is smooth for a min.and then it's the same problem and the engine dies.
If I wait for 3 min. the car simply won't start even though the start motor is running fine.It takes about 2 hours before I can start it again and it starts in a sec. and runs fine till it gets hot again.
If I don't stop I can drive it for 20 min and maybe more, I haven't tried more.
Any help out there?

 

Wrong forum.....I'm sure someone will move this to the right forum for you.

But as long as I'm here.....

I had a similar problem with my 92 Z28 about 10 years ago. Only difference is, mine wouldn't surge, it would just die shortly (and a few times even before) it warmed up and the accelerator was up. As long as I kept my foot on the accelerator, it would run fine, but as soon as I let off, it would instantly die. Sometimes it would fire right back up, sometimes it wouldn't start until the next day.

I replaced the ignition module....problem solved.

It's possible for an auto parts place to "bench check" the module and it may seem to be fine, but there's no way to check how it'll act when it warms up.

Not sure how expensive parts are over there, but if I remember correctly it ran me around $20 or so.

Good luck and welcome to the board !

 

Thanks for your answer.
I tried to answer before but I got "you are not logged in" and then I couldn't log in.
I changed the ignition module but I still have the same problem.
I think I have a sensor problem even though the computer showes no errorcodes or sensor malfunction.
I doesn't seem to be anyone that can help me, I've asked 6 different car experts but they don't have a clue and/or time. My regular repair guy is out of ideas so this (and other) forums is my only hope.
So please guys, if you have ANY ideas, answer my cry out for help.
The car is far to good to end up in the junk yard.

 

A few things that could help us figure it out.

Have you checked the fuel pressure?
Does the exhaust smell of raw gas (petrol)?
Have you had the Idle Air Controler replaced?
Have you checked to see if you have a vacuum leak or if the EGR is messed up?

 

Fuel pressure is checked and fund ok according to my service guy.
No smell of gas, I think that the fuel is for some reason turned off.
IAC is not changed, the idle is ok until the engine is warm.
If I had a vacuum leak, wouldn't that effect the car also when it's cold?
The EGR is tested ok.
I drove it for 15 minutes today and sprayed the inside of the ECM with cooling spray, same problem.

 

There's temperature vacuum switches on thethemostat housing that only open up when warm. Any connection after that can be suspect.

I'd still check it. I've had sensors fail when they get warm and then be okay when they cool down.

 

The temperature vacuum switch is very interesting.
It sounds to me that it could be the guilty one.
I keep the car in a small barn over the winter since it's a conv. and I know there are mice. We put out poison but who knows.
Have to check that out on Monday, it's busy weekend.
Thanks