Well heres my problem now... My 98 sunfire was in an accident before i got it. The guy drove it home and overheated it. i replaced everything that busted got a junkyard head and rebuilt it then put it all back together. Now heres what happens... I start it and it starts right up and runs fine for a few seconds then dies. I checked everything. I have fuel, spark, compression, and vacuum is also good. It also runs fine on carb cleaner. it runs great, no roughness or smoke or anything. Starts very strong too. My question is... Why wont it stay running on its own??? Could it be a theft thing? because i also changed the key & tumbler? But it starts fine so im thinking it cant be that... Im also wondering if because of the accident there was a fuel cutoff for safety??? Something is cutting off the fuel, but it runs great before that so its getting fuel..... im lost, Any ideas would be MUCH appreciated....

have you looked to see what the fuel pressure is? I had a similar problem with my ta. Mine turned out to be a bad BCM. I had fuel pressure at startup and then after running for 5-6 seconds I lost fuel pressure and the car died. Through the whole thing I learned that EVERY number on the GM modules MUST match to work.

problem was the Passlock system. I just got done test driving it!