Well, im new here, and the proud owner of my first 3rd gen, finally! Ive been going through doing all my basic tune up stuff before i try to get it smogged. But i have a question concerning the idle. ITs alittle rough. not real bad, like a miss, but rough enough that you can feel it when your sitting in the car or leaning against it. Its a 92 TBI 305 firebird. So far, ive done plugs, wires, cap and rotor, Checked and cleaned the IAC, checked for vacume leaks, Replaced the TPS to clear a Code 22. What im really curious about is how smooth to expect the idle to be.
It seems to get worse as it warms up. Smoother when its cold. Starts great, hot or cold, consistant idle, maybe only flutuates 50 RPM or so.

 

What are you comparing the smoothness of the idle to? How many miles on the engine? What isthe vac reading at idle?
There are a lot of things that could cause this.

 

Havent got a vacume gauge on it yet. Dont have one at home. I have a 93 jeep cherokee and a 95 mercury cougar 4.6. Both idle nice and smooth. Not that its a good comparison. The car has 131,000 on it. When i get a chance, i need to do a compression test as well. All but one plug looked good when i pulled them. One was pretty black. Ive never had a TBI car before, only carbs and MPI cars.