I was wondering if someone on here could help me with a problem I'm noticing on my 94 z28 m6. About a week ago I notice that when I let the car idle after driving it a short distance it would fluctuate down to about 400-500 rpms and then surge up to about 1000. It sometimes would right itself and sometimes it wouldn't surge and it would just die. This would happen at stop lights or just when I was trying to shift and took my time. Sometimes this happens and sometimes it doesn't. I've noticed no performance loss but I do notice all my electrical stuff in the car goes out right before it dies. I figure it is b/c the engine is idling so low and not making enough juice. Anyways, today I went to start it up and it would fire up and then do the same thing with the rpms and then die. I had to give it gas like a carbed motor when it is cold just to keep the rpms up. Once I drove it for a minute it stopped doing it. I just can't figure it out. It is so random when it occurs. Sorry it is so long but I don't want to have to take it in to get looked at and any suggestions would be greatly appreciated. Thanks in advance.
Chad

 

A couple of things could be your problem. The IAC is the first thing to look at and clean it thoroughly. The next thing to look at is any vacuum leaks. The last thing is a sticky EGR may need cleaning.

 

I know what the IAC is but how and where would I check for vacuum leaks and a sticky EGR? I'm pretty new with all of this and your help is greatly apreciated. Thanks for the quick response.

 

I'm so sorry it took me so long to respond. I have a business and it takes so much time. anyway, here is a close up of the EGR. http://shbox.com/1/intake_rear.jpg

It is at the back of the intake right up near the fire wall.

As far as vacuum leaks you can listen and use a spray like wd40 at hose connections to listen for engine performance changes.

Let us know if you need more help.

 

Thank you for all of your help. I'm going to take a look at it tomorrow and see if I can figure out what the problem is. I just want to say thanks again for the info. and that this site has been very helpful. Keep up the good work!
Chad