Wasup fellow 6GC'ers ....I got this problem with my 94 Celica ST whenever i start my car in the morning it turns on then shuts off.
When i try again, and keep my foot on the gas so it stays on, i raise the idle to 1000RPM-1300RPM but as im doing that, the engine
runs rough almost rumbling and it stays doin that until it warms enough to keep idle on its own. I have headers on my 7AFE but the gasket
to the header that meets the down pipe is burnt so i have an exhaust leak.

I live in Boston, MA so its cold but wondering if anyone
had any useful insight on what it might be.

Im guessing maybe my idle air control sensor?

Everybody and their brother seems to be having this issue, me included.
http://www.6gc.net/forums/index.php?showtopic=70359

I also have to keep my foot on the accelerator at what would be fast idle for 30 or so seconds until I hear what sounds like a click of a relay or something and it takes over & idles fine like nothing happened.

IAC was mentioned, but that hasn't been confirmed yet.

Spray it with some throttle body cleaner while its running. A little of starter spray helps a lot in cleaning out stuff.