Important: Over extended time and mileage, deposits may accumulate on the back of the throttle valve plate. The source of the deposit is EGR gas. 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).

Caution: Turn OFF the ignition before inserting fingers into the throttle bore. Unexpected movement of the throttle blade could cause personal injury.

1. Remove the air intake duct.

Notice: Do not insert any tools into the throttle body bore in order to avoid damage to the throttle valve plate.

2. Inspect the throttle body bore and the throttle valve plate for deposits. If necessary, open the throttle valve to inspect all surfaces.

Notice: Do not use any solvent that contains Methyl Ethyl Ketone (MEK). This solvent may damage fuel system components.

3. Clean the throttle body bore and the throttle valve plate using a clean shop towel with an appropriate cleaning substance, such as one of the following:

•	GM Top Engine Cleaner

•	P/N 1052626 (Canadian P/N 993026)

•	AC-Delco Carburetor Tune-Up Conditioner

•

P/N X66-P

4. Install the air intake duct.