???Don't know of anything that's routinely referred to as the "iac screw".....not sure what you're asking about. The throttle stop screw should be turned (clockwise) 1/4 turn past where it just touches the throttle body arm - to keep the throttle plate from sticking in the housing. Technically, the idle isn't adjustable on the cars. It's held at about 675-700 rpm by the ecu - using the IAB solenoid and ignition timing.