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Home >> Oldsmobile >> 2000 >> Intrigue GL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0300-P0306: Engine Misfire Detected >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Check for replacement of engine, PCM, CKP sensor, crankshaft reluctor or other conditions causing incorrect CKP system variation data. Using scan tool, perform CKP system variation learn procedure. After performing CKP learn procedure, go to next step.
  3. Check for DTCs. If other DTCs are set, diagnose affected DTCs first. If no other DTCs are set, go to next step.
  4. Using scan tool, select MISFIRE BAR GRAPH or MISFIRE CURRENT COUNTERS. Start engine. If any cylinders indicate an excessive amount of misfire, go to next step. If cylinders does not indicate an excessive amount of misfire, see DIAGNOSTIC AIDS .
  5. If misfire appear to be affecting specific cylinders, go to step  14. If misfire dos not appear to be affecting specific cylinders, go to next step.
  6. Check vacuum hoses for splits, kinks or improper connections. Repair as necessary. After repairs, go to step  19. If vacuum hoses are okay, go to next step.
  7. Check PCV valve for damage or improper installation. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  8. Check throttle body inlet and duct for damage or restriction. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  9. Check fuel pressure. See BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  10. Check fuel for excessive water, alcohol or other contaminants. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  11. Check grounds to PCM and ignition control module. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  12. Check for vacuum leaks at intake manifold, EGR adapter, EGR valve, EGR feed pipe and injector O-rings. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  13. Remove EGR valve. Check EGR pintle for carbon deposits or burrs causing pintle from closing completely. Repair or replace EGR valve as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  14. Check secondary ignition. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  15. Check for proper fuel injector operation. Perform fuel injector balance test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  16. Check vacuum leaks that may affect one cylinder more than others. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  17. Check for damaged drive belt or pulley, generator, water pump or belt tensioner. Check for basic engine mechanical problems. Check for loose or broken motor mount. Repair as necessary. After repairs, go to step  19. If no problem was found, go to next step.
  18. Check for transaxle torque converter clutch problem. Repair as necessary. After repairs, go to next step. If not problem was found, see DIAGNOSTIC AIDS .
  19. Using scan tool, review and record FREEZE FRAME data. Clear DTCs. Turn ignition off and wait 15 seconds. Operate vehicle under conditions noted in FREEZE FRAME data. Monitor misfire display for each cylinder. If misfire current is incrementing for any cylinder, go to step  3. If misfire current is not incrementing for any cylinder, go to next step.
  20. Using scan tool, select CAPTURE INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no DTCs are displayed, system is okay.
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