For 1990-2009 cars

Cause | Correction
--- | ---
Worn or loose Stationary Hydraulic Lash Adjusters (SHLAs), valve rocker arms. The SHLAs, valve rocker arm, roller bearing should be intact and in the correct position. | Replace the SHLAs, valve rocker arms, as required.
Sticking valves. Carbon buildup on the valve stem can cause the valve not to close correctly. | Repair or replace as required.
Worn or mis-aligned above acceptable tolerances timing chain or chains. | Replace the timing chain or chains and sprockets as required.
Worn camshaft lobes. | Replace the camshaft or camshafts and high SHLAs, valve lifters.
Sticking SHLAs, lifters. | Replace the SHLAs as required.