C 3500 Truck 2WD V8-454 7.4L (1990)
Idle Speed: Adjustments
Idle Speed
1985-86 2.5L (151) FI: Remove air cleaner assembly and disconnect Idle Air Control (IAC) multi-plug. Start engine and allow idle to stabilize. Install
special tool in the idle air passage of the throttle body and turn throttle stop screw to obtain the specified setting speed.
1987-90 All: Ground diagnostic terminal (see COMPUTER DIAGNOSTIC CODES), turn ignition on but do not start engine. Wait 30 seconds then
disconnect the IAC connector. Remove ground from the diagnostic terminal, start engine and turn throttle stop screw to obtain the specified setting
speed.
