Symptom Diagnosis

Symptom checks should not be used unless symptom occurs while vehicle is being tested. To reduce diagnostic time, ensure basic diagnostic tests in the BASIC TESTING article and self-diagnostic procedures in the TESTS W/CODES article were performed before diagnosing a symptom. Symptoms available for diagnosis include:

• Hard Start
• Stalls After Starting
• Hesitation, Sag Or Stumble
• Vehicle Surges Or Chuggles
• Lack Of Power Or Sluggish
• Engine Backfires
• Cuts Out, Misses
• Rough, Unstable Or Incorrect Idle
• Engine Will Not Idle
• Poor Fuel Economy
• Engine Dieseling/Run-On
• Detonation/Spark Knock
• Excessive Exhaust Emissions Or Odors