Engine Mechanical
WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Check the following:
- Engine compression. See ENGINE COMPRESSION TEST under MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 4.0L AURORA article.
- Sticking or leaking valves, worn camshaft lobes, valve timing, worn rocker arms, broken or weak valve springs and excessive oil in the combustion chamber (leaking valve seals). See appropriate article in ENGINES.
- Check for incorrect basic engine parts. Check the camshafts, cylinder heads, pistons, etc. See appropriate article in ENGINES.