Important: Over an extended period of time and mileage, deposits may accumulate on the back of the throttle plate. Typically these deposits pose no problems. Occasionally the deposits may accumulate to a point where throttle valve movement is effected. This procedure should not be performed on vehicles with mileage under 80 450 km (50,000 mi).

1. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical.
2. Remove the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .
3. Inspect the throttle body bore and the throttle body plate for deposits. You will need to open the throttle plate in order to inspect all surfaces.
4. Clean the throttle body bore and the throttle plate using a clean shop towel with GM top engine cleaner, P/N 1052626 or AC Delco Carburetor Tune-up Conditioner, P/N X66P, or equivalent product.
5. Install the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .
6. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical.