Symptom Diagnosis

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC TESTING and appropriate G - TESTS W/ CODES articles in the ENGINE PERFORMANCE section below were performed before diagnosing a symptom. Symptoms available for diagnosis include:

• Hard Start
• Hesitation, Sag Or Stumble
• Vehicle Surges
• Lack Of Power Or Sluggish
• 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
• TESTS W/CODES - 4.6L
• TESTS W/CODES - 4.9L