"Rodan" wrote: (1992 Buick Roadmaster 350 TBI).
Idles at 1200-1500 RPM cold or hot, runs rough, feels exactly like a stuck automatic choke, but there is no choke - it's fuel Check the gasket between the throttle body and intake manifold. I'll bet it's sucked in. ___________________________________________
Well, I checked everywhere for vacuum leaks, including under the throttle body, and didn't find the problem. As usual, I decided to start throwing parts and money at it. I bought a new IAC valve first, thinking it might lower the idle speed, so I could then look for the miss.
Miraculously, the IAC valve fixed everything; the idle dropped to the correct 550 rpm and the rough running vanished.
So why am I thanking aarcuda? Because he took the time to offer a suggestion from his experience which I might never have considered. I have been spared many dollars and skinned knuckles by the knowledge shared here by alt.autos.gm posters. And I do the same for others here even though I am sometimes ridiculed by professional auto technicians.
Thanks again to aarcuda, and to all those who have the courtesy and the courage to offer help to others.
Rodan.