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

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 .

Improper operation of the active fuel management oil pressure relief valve

Repair, as required. Refer to Cylinder Deactivation (Active Fuel Management) Oil Pressure Relief Valve Diagnosis and Testing .

Improper operation of the active fuel management system

Repair, as required. Refer to Cylinder Deactivation (Active Fuel Management) System Diagnosis .

Improper operation of the camshaft position (CMP) actuator and/or control system

Repair, as required. Refer to Camshaft Position Actuator and Solenoid Valve Diagnosis and Testing .