Symptom Diagnosis

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

• Engine Won't Start
• Engine Starts But Stops
• Rough or Unstable Idle
• Poor Response On Acceleration
• Engine Hesitates or Misses
• Poor Fuel Mileage
• Lack of Power