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Home >> Isuzu >> 2000 >> Rodeo LSE, 2.2 D >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Trouble Code Identification >> DTC P0301-P0304: Random/Multiple Cylinder Misfire Detected >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic II (OBD-II) system check. See SELF-DIAGNOSTICS - INTRODUCTION article. Go to next step.
  2. Start engine and allow it to idle. Using scan tool, read and record FREEZE FRAME data. Operate vehicle within conditions noted in FREEZE FRAME data. Using scan tool, read MISFIRE CUR # display for each cylinder. If MISFIRE CUR # is increasing (indicating a misfire currently occurring) for any cylinder, go to next step. If MISFIRE CUR # is not increasing, go to DIAGNOSTIC AIDS .
  3. Check vacuum hoses for splits, kinks, or improper connections. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  4. Check intake manifold, injector "O" rings, EGR valve, and EGR feed pipes for vacuum leaks. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  5. Check PCV valve for improper installation or damaged hose. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  6. Remove ignition coils. Check ignition coils for cracks or carbon tracking. If a problem is found, replace damaged ignition coils. Retest system. If no problem is found, go to next step.
  7. Install a spark tester on spark plug wire at spark plug end for cylinder indicated by DTC. Crank engine and check for crisp, Blue spark at tester. If spark is okay, go to step  12. If spark is not okay, go to next step.
  8. Remove spark plug(s) associated with misfiring cylinder(s). Check spark plugs for excessive fouling. If spark plugs are excessively fouled, diagnose and repair mechanical engine problem. If spark plugs are not excessively fouled, go to next step.
  9. Check spark plug insulation for cracks, carbon tracking or other damage. If a problem is found, replace faulty spark plug(s). Retest system. If no problem is found, go to next step.
  10. Replace ignition control module. Retest system.
  11. Check PCM injector, power and sensor grounds for clean and tight connection, and for proper location. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  12. Perform a fuel pump pressure test. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If a problem was found, repair as necessary. Retest system. If no problem was found, go to next step.
  13. Check for fuel contamination. If fuel is contaminated, repair condition causing contamination. Retest system. If fuel is okay, go to next step.
  14. Perform FUEL INJECTOR BALANCE TEST under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If a problem was found, repair as necessary. Retest system. If no problem was found, go to next step.
  15. Diagnose mechanical engine problems such as faulty or incorrect camshaft, leaking valves or piston rings, sticky valves, excessive valve deposits, loose or worn rocker arms, weak valve springs, incorrect valve timing, leaking head gasket, or loose or broken motor mounts. If a problem is found, repair as necessary. Retest system.
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