my 305 Tpi firebird wont stay on it runs great when i keep my foot on the gas but when i let off it shuts down...... I just replaced the fuel filter so im thinking it could be the pump but it sounds like the pump is running fine .... does anyone know what it could be ?

One thing you could check is the TPS voltage. It's the three-wire sensor on the pass side of the throttle body.
Turn the key on and check all three wires. One should read 0V (ground), another one close to 5V (power) and the last one should show 0.5V (signal at idle). If you don't see these voltages, that's the culprit of the stalling.

It could also be the AIC but it's a little more involved to reset it.

Actually, it could be more things but you can start with the TPS

When did the problem start? Did anything trigger it? Did it start slowly or all of a sudden?

Lou

No it ran fine home .... perfect then i woke up in the morning and it started

You mean IAC, right? I'm betting that's exactly what it is. The pintle is probably stuck with carbon buildup. Take out the IAC and try knocking some of the carbon out. Clean it up a bit. (without using liquids or chemicals). If cleaning it doesn't work out, i'd buy a new one. Sometimes IAC's can be a little difficult to fully clean. I've had this problem before and that's exactly what it was.

Yeah, check the TPS voltage. then clean off the IAC. Use a toothbrush to clean the cavity the pintle sticks into. Be careful, it will be gunked (mine was terrible), don't damage the pintle. Also, spray TB cleaner into the IAC air passages.

Right. Sorry, I always mistype that.

Lou

Thanks guys .... thats exactly what it was .... it runs great now

Glad to hear you're up and runnin'!