Grand Prix V8-5.3L (2007)
^
If there is no fluctuating drop in engine vacuum, or the engine does not misfire, then refer to Cylinder Deactivation (Active Fuel Management)
System Diagnosis.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. See: Testing and Inspection/Diagnostic Trouble Code Tests and
Associated Procedures/Verification Tests and Procedures