Symptom Diagnosis

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

• Hard Start
• Hesitation, Sag Or Stumble
• Vehicle Surges Or Chuggles
• Lack Of Power, Sluggish Or Spongy
• Engine Backfires
• Cuts Out, Misses
• Rough, Unstable Or Incorrect Idle, Stalling
• Poor Fuel Economy
• Engine Dieseling/Run-On
• Detonation/Spark Knock
• Excessive Exhaust Emissions Or Odors