Worn valves, valve guides and/or valve stem oil seals

1. Inspect the spark plugs for oil deposits. Refer to Spark Plug Inspection .
2. Repair or replace, as required.

Improper operation of the positive crankcase ventilation (PCV) system

Repair or replace, as required.

Damaged or worn piston and/or rings

Oil consumption may or may not cause the engine to misfire.

1. Inspect the spark plugs for oil deposits. Refer to Spark Plug Inspection .
2. Inspect the cylinders for a loss of compression. Refer to Engine Compression Test .
3. Perform cylinder leak down and compression testing to determine the cause.
4. Repair or replace, as required.