Thread: sustained high idle problem 93 tbird 3.8L

I have a sustained 2500 rpm idle on a 93 thunderbird 3.8L that I can't figure out. I disconnected the air hose on the side of the throttle body and the idle went way down (tries to die). The throttle body butterfly valve does not appear to have any buildup blocking it's movement (appears very clean and functions as it should). I replaced the air hose and unhooked the air flow sensor - engine dies (as it should). I replaced the idle air control valve with a new one - same problem. I removed the air filter - same problem. Prior to replacing the iac valve, I tried one from a 96 6cyl mustang and idle goes way down and tries to die (have to adjust idle set screw to keep it running) but then there was little to no power. What am I missing?

Also check your butterfly for carbon build up

I have checked for vacuum leaks and there doesn't appear to be any. The butterfly valve doesn't appear to have any carbon buildup on it either and is moving freely all the way shut (no buildup or blockage). What would be the "symptoms" if a mass air flow sensor was to go bad?

what would be the "symptoms" if the mass air flow sensor were to go bad?

bad gas mileage, poor throttle response. Does you car flash any codes to you? Seeing that it is obd1