Base Engine Misfire with Abnormal Valve Train Noise

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Cause	Correction
Engine oil level overfull, causing aeration	Drain excess oil and adjust oil level to proper specification.
Worn or loose rocker arms-The rocker arm bearing end caps and/or needle bearings should intact within the rocker arm assembly.	Replace the valve rocker arms as required.
Worn or bent pushrods	Replace the pushrods.
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 lifters	Replace as required.
Malfunctioning camshaft position actuator-Improper viscosity oil, contaminated oil, or a plugged or missing camshaft position actuator filter can cause the camshaft position actuator locking pin to malfunction.	Verify correct oil viscosity by changing the engine oil and oil filter and re-evaluating the concern. Inspect for a missing or plugged camshaft position actuator filter. If filter is missing, replace the filter, replace the camshaft position actuator, and change the engine oil and oil filter. If filter is plugged, replace the filter, and change the engine oil and oil filter. If no problem is found with the camshaft position actuator filter, replace the camshaft position actuator and change the engine oil and oil filter.