Important Preliminary Inspections Before Starting

Before using this section, perform the Diagnostic System Check - Vehicle in Vehicle DTC Information and verify all of the following conditions:

• The engine control module (ECM) and the malfunction indicator lamp (MIL) are operating correctly.
• Diagnostic trouble codes (DTCs) are not stored.
• The scan tool data is within the normal operating range. Refer to Scan Tool Data List .
• Verify the customer concern and locate the correct symptom. Inspect the items indicated under that symptom.
• Several of the symptom procedures ask for a careful visual/physical inspection. This step is extremely important, and can lead to correcting a condition without further inspections and can save valuable time.
• If the intermittent condition exists as a start and then stall, inspect for any DTCs related to the theft deterrent system. Refer to Diagnostic System Check - Vehicle in Vehicle DTC Information.
• Verify the proper installation of any of the following non-original equipment accessories:
  • Lights
  • Cellular phone
  • Remote starter system
  • Non-factory installed alarm

1. Use the following tables when diagnosing a symptom concern:
   • Poor Fuel Fill Quality 
   • Hard Start 
   • Surges/Chuggles 
   • Lack of Power, Sluggishness, or Sponginess 
   • Detonation/Spark Knock 
   • Hesitation, Sag, Stumble 
   • Cuts Out, Misses 
   • Poor Fuel Economy 
   • Rough, Unstable, or Incorrect Idle and Stalling 
   • Dieseling, Run-On 
   • Backfire 
2. If the condition can not be isolated using the appropriate table, refer to Intermittent Conditions  for further diagnosis.