'91 RS Starting Problems...

I've got a '91 RS with the 3.1 V6 in it.

The car would start and run for a few seconds and shut off, previously. Since then, I've replaced several ignition components, fuel pump, filter, and pressure regulator.

After replacing the fuel pressure regulator and the rotted out vacuum line that was attached to it, the car runs great. But only when the engine is cold. Once the engine has reached operating temperature (around 220) it sputters and eventually dies. Sometimes it will start right back up, and sometimes it won't.

If it leave it setting long enough to cool down, it will fire right back up as if nothing was wrong.

I've been stumped with this for quite some time, and have finally decided to look for some kind of help with this issue.

Any information that anyone could provide would be greatly appreciated.

Thanks in advance.

Did you replace the ignition module? If you did...did you replace it with an AC Delco one? If the answer to either question is no....take the module to an auto parts store and see if they will test it for you. They need to run the tests several times to get the module good and hot and see if it fails. If it fails even once during the testing, replace it with an AC Delco module.