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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISENGINE PERFORMANCEREMOVE, OVERHAUL & INSTALLENGINE CONTROLS - REMOVAL & INSTALLATIONAIR INDUCTION SYSTEMSINTAKE MANIFOLDREMOVAL (5.3L)
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Removal (5.3L)

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Removal (5.3L)
NOTE: The intake manifold, throttle body, fuel rail, and injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.
  1. Remove the air cleaner outlet duct. See AIR CLEANER RESONATOR OUTLET DUCT .
  2. Relieve the fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE .
  3. Disconnect the air conditioning (A/C) compressor pressure switch electrical connector (2). See Figure.
  4. Remove the harness clip from the cylinder head.
  5. Disconnect the MAF/IAT sensor electrical connector (1). See Figure.
  6. Remove the harness clips from the fuel rail.
  7. Disconnect the following electrical connectors:
    • Main coil (1). See Figure.
    • Electronic throttle control (ETC) (2).
    • Fuel injectors (3).
  8. Perform the following steps in order to disconnect the fuel injector electrical connector.
    • Mark the connectors to their corresponding injectors to ensure correct reassembly.
    • Pull the Connector Position Assurance (CPA) retainer (2) on the connector up 1 click. See Figure.
    • Push the tab (1) on the connector in.
    • Disconnect the fuel injector electrical connector.
    • Repeat the steps for each injector electrical connector.
  9. Disconnect the generator electrical connector. See Figure.
  10. Disconnect the following electrical connectors:
    • Evaporative emission (EVAP) purge solenoid (1). See Figure.
    • Knock sensor (2).
    • Manifold Absolute Pressure (MAP) sensor (3).
    • Main coil (5).
    • Fuel injectors (4).
  11. Remove the electrical harness clips from the fuel rail.
  12. Remove the knock sensor harness electrical connector from the intake manifold.
  13. Remove the Positive Crankcase Ventilation (PCV) hose. See Figure.
  14. Remove the heater water shutoff valve actuator inlet hose from the intake manifold. See Figure.
  15. Remove the Evaporative emission (EVAP) purge solenoid vent tube by performing the following:
    • Remove the EVAP tube end from the solenoid. See Figure.
    • Squeeze the EVAP pipe quick connect fitting retainer together.
    • Remove the EVAP tube end from the vapor pipe.
  16. Remove the vacuum brake booster hose from the rear of the intake manifold. See Figure.
  17. Remove the upper engine wire harness retainer nut (1). See Figure.
  18. Reposition the upper engine wire harness aside.
  19. Remove the intake manifold bolts.
  20. Remove the intake manifold. See Figure.
  21. Remove the intake manifold gaskets (1) from the intake manifold. See Figure.
  22. Discard the old intake manifold gaskets.
  23. If necessary, clean and inspect the intake manifold.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.