Symptom Diagnosis

Symptom checks should not be used unless symptom occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC DIAGNOSTIC PROCEDURES - 4.6L DEVILLE & SEVILLE and SELF-DIAGNOSTICS - 4.6L DEVILLE & SEVILLE articles were performed before diagnosing a symptom. Symptoms available for diagnosis include:

• CUTS OUT, MISSES 
• DETONATION/SPARK KNOCK 
• ENGINE BACKFIRES 
• ENGINE DIESELING/RUN-ON 
• HARD START 
• HESITATION, SAG OR STUMBLE 
• LACK OF POWER, SLUGGISH OR SPONGY 
• POOR FUEL ECONOMY 
• POOR FUEL FILL QUALITY 
• ROUGH, UNSTABLE OR INCORRECT IDLE & STALLING 
• VEHICLE SURGES OR CHUGGLES