Diagnostic Aids
- Other electrical, fuel, or mechanical conditions can cause an engine to crank but does not run, or set a DTC P0300 misfire code.
- This Electronic Ignition (EI) System diagnostic test assumes that the vehicle battery is fully charged.
- An ignition coil, boots, or spark plugs may misfire only when moisture is present. Although difficult to test on this engine, selectively wetting down parts of the ignition system and monitoring for a misfire may help in isolation an intermittent condition. Replace any worn or torn spark plug boots or seals.
- Intermittent conditions. See INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.6L DEVILLE & SEVILLE article.