Hello,

I recently purchased a 1990 Pontiac Sunbird LE (coupe, non-turbo, 3 A/T).

When I got the car, the idle was always at 2500rpm. Turned out to be the PCM. Changed it and it now runs quite well. I’ve got a little problem though: the previous owner played with the base idle screw to try and lower the idle speed. I would now like to set it back to where it is supposed to be. Any of you know the correct procedure to set the base idle speed so that the car doesn’t go crazy with the IAC adjustments?

Thanks in advance!

Back the screw out until it is no longer touching the throttle lever. Then turn it in until it just touches the throttle lever. Once it makes contact with the lever, turn the screw in 1 and 1/2 turns.