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 deposit may accumulate to a point where throttle valve movement is affected. This procedure should not be performed on vehicles with low mileage, under 80 450 kilometers (50,000 miles).

1. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement .
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. It is necessary to open the throttle valve in order to inspect all of the 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 injection sight shield cover. Refer to Fuel Injector Sight Shield Replacement.