For 1990-2009 cars

1. Remove the air cleaner outlet duct.
2. Inspect the throttle body bore and throttle plate for deposits. You must open the throttle plate in order to inspect all of the surfaces.
3. Clean the throttle body bore and the throttle plate using a clean shop towel and top engine cleaner, GM P/N 1052626 (Canadian P/N 993026), or equivalent.
4. After disassembly, clean the throttle body using a parts cleaning brush. DO NOT immerse the throttle body in any cleaning solvent.
5. Install the air cleaner outlet duct.