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 article in this section and TESTS W/CODES - ECM/PCM article in this section 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