GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Stuck valves

Carbon buildup on the valve stem can cause the valve not to close properly.

Repair or replace as required.

Excessively worn or mis-aligned timing chain

Replace the timing chain and sprockets as required.

Worn camshaft lobes

Replace the camshaft and valve lifters.

Sticking or worn lifters

Replace as required.