Symptom Diagnosis: Notes

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 TESTS W/CODES articles were performed before diagnosing a symptom. Symptoms available for diagnosis include:

• Difficult or no start (cranks okay)
• Rough or unstable idle
• Excessive fast idle
• Engine stalls
• Engine misfires or has lack of power
• Engine runs rough on deceleration
• Afterburn in exhaust system
• Poor fuel mileage
• Excessive oil consumption
• Abnormal noise or knocking