Symptom Diagnosis: Notes

Symptom checks cannot be used properly unless the problem is actually present while the vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC TESTING and TESTS W/CODES articles have been performed before attempting to diagnose a symptom. Symptoms available for diagnosis include the following:

• Engine won't start.
• Difficult cold start.
• Fast idle out of specification.
• Rough idle when warm.
• Idle RPM high when warm.
• Idle RPM low when warm.
• Stalling during warm up.
• Stalling after warm up.
• Misfire or rough operation.
• Emission test failure.
• Lack of power.

  Recommended system and component checks may not apply to all vehicles.