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.

Worn piston 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.