I know this is a firebird/camaro forum but I dont think theres any other place I could go with this much experience with this engine. Its a 2.8L Fiero GT. The problem is when it idles .. on startup it runs like it should then 30 seconds or so it idles down and bounces inbetween 1200 to 400rpms and eventually dies. While driving its fine except when I have to stop and let the engine idle. Ive changed the idle control valve, map sensor, both temp sensors, dont see any visably broken or disconnected vacuum lines. The SES light wont come on so I dont think its throwing any trouble codes. Ive made sure the timing was good, air cleaner was ok, coil and wires have good contact, it doesnt miss while running at anything higher then idle. To drive it when i come to stop lights i have to put it in neutral and lightly tap the gas to keep it from dying. Im stumped as to what could be doing this, any suggestions or ideas, I know its not a firebird but its the same engine and I figured someone here that knows that motor might have info.

 

check for a vacuum leak