Symptom Diagnosis

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

• Difficult to start
• Surges or chuggles
• Lack of power or sluggish
• Detonation or spark knock
• Hesitation or stumble
• Cuts out or misses
• Poor fuel mileage
• Rough, unstable idle or stalls
• Excessive exhaust emissions or odors
• Runs-on or diesels
• Backfires