Hello Everyone.. Newbe here... I was wondering if I could get some of your expert help. I have a 95 Monte Carlo Z34 with 220K miles. The car runs good, A little rough on cold start up but runs fine when warmed up. The problem I am having is after the car warms up and has been driven awhile. when you turn it off and come back a few min later the car wont start. It cranks no problem, but wont start. If you let it sit for 10-15 min. It starts right up.... Anyone else have this problem or know what the problem might be??? Thanks in advance for any help

 

When was the last time you changed the fuel filter?
Also, I would do a fuel pressure check at the fuel rail when it won't restart...That could be a sign that you may have a failing fuel pump.
lm sure someone else will chime in with other idea/possibilities.
Thanks for joining the MCF family.

 

Have the ignition control module (ICM) tested. Make sure they run several consecutive tests to get it nice and hot. It sounds to me like the ICM is shorting out once it is hot. Once it cools down (10-15 minutes) the car starts back up...very common symptom of a bad ICM...

 

Great Idea!
Now, why didn't I think of that?
Thanks again Mike.

 

another thing to check is the fuel pressure regulator...pull the vacuum line off of the regulator and see if there is any fuel going into the vacuum line...if the nipple to the regulator is wet or the vacuum line has any fuel come out of it, the regulator is bad...check the easy stuff first...the control module on a 95 is in a crappy place, on the rear of the rad and not easy to get to...when it does act up, hook up a spark checker and crank the engine...if it does not light up, then yes the control module may be the problem as well as the crank sensor

 

Thank you all for your help. I will check out all your suggestions

 

I had this problem with my 02 about 3 weeks ago. I too thought it was the IAC. Turned out it was a bad signal from my MAS. I know we have different engines. Just thought you should test your MAS too.