Air/Fuel Mixture: Testing and Inspection

The technician should be aware that diagnosis and testing of the Air/Fuel mixture, such as biased "rich or lean" conditions should begin at the Powertrain Management level, where testing begins with Diagnosis by Symptom, and is narrowed to testing of a "specific" subsystem and it's related wiring and components. Following the appropriate diagnostic routines may prevent misdiagnosis and unnecessary component replacement. Refer to Powertrain Management/Testing and Inspection/Procedures.