Note:Over extended time and mileage, deposits may accumulate on the back of the throttlevalve plate. The source of the deposit is exhaust gas recirculation (EGR) gas. Typicallythese deposits pose no problem. Occasionally the deposit may accumulate to a pointwhere perceived pedal effort or throttle valve movement is effected. This procedureshould not be performed on vehicles with mileage under 80-450-km(50,000-mi).
Remove the air cleaner outlet duct resonator. Refer toAir Cleaner Outlet Resonator Replacement.Warning:Turn OFF the ignition before inserting fingers into thethrottle bore. Unexpected movement of the throttle blade couldcause personal injury.
Caution:Do not insert any tools into the throttle body bore in orderto avoid damage to the throttle valve plate.
Inspect the throttle body bore and the throttle valve plate for deposits. You willneed to open the throttle valve in order to inspect all surfaces.Caution:Do not use any solvent that contains Methyl Ethyl Ketone(MEK). This solvent may damage fuel system components.
Clean the throttle body bore and the throttle valve plate using a clean shop towelwith GM top engine cleaner, GM-P/N-1052626 (Canadian-P/N-993026) or ACDelco CarburetorTune-Up Conditioner, P/N X66-P, or an equivalent product.Install the air cleaner outlet duct resonator. Refer toAir Cleaner Outlet Resonator Replacement.Perform the Throttle/Idle Learn procedure. Refer toQ38 Throttle Body: Throttle/Idle Learn.Brake Pedal Travel Measurement and Inspection Hydraulic Brakes Brake Pedal Assembly
Special ToolsJ-28662Brake Pedal Effort Gauge, or equivalentWith the ignition OFF and the brakes cool, apply the brakes3–5-times, or until the brake pedal becomesfirm, in order to deplete the brake booster power reserve.Install theJ-28662Brake Pedal Effort Gauge, or equivalentto the brake pedal.Mea ...