For 1990-2009 cars

Cause | Correction
--- | ---
Worn or loose rocker arms The rocker arm bearing end caps and/or needle bearings should be intact within the rocker arm assembly. | Replace the valve rocker arms, as required.
Worn or bent pushrods |

• | Replace the pushrods.

• | Inspect the top of the pistons for valve contact. If the top of the piston shows valve contact, replace the piston and pin assembly.

Stuck valves Carbon buildup on the valve stem can cause the valve to not 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 lifters | Replace, as required.
Cut or damaged oil pump screen O-ring seal which may cause aeration of the engine oil | Repair, as required. Refer to Oil Pressure Diagnosis and Testing .