Engine Mechanical

Inspect the following conditions:

1. Cylinder compression. See ENGINE COMPRESSION TEST in BASIC DIAGNOSTIC PROCEDURES - 4.6L DEVILLE & SEVILLE article.
2. Sticking or leaking valve.
3. Worn camshaft lobes.
4. Valve timing.
5. Worn rocker arms, or broken valve springs. See appropriate article in ENGINES.
6. Excessive oil in the combustion chamber - leaking valve seals.

Inspect for incorrect basic engine parts. Inspect the following:

1. Camshaft
2. Cylinder Heads
3. Pistons, etc.