Removal Procedure

Important:  The fuel injector wiring harness connectors must be connected to their respective fuel injectors. Failure to connect the fuel injector connectors to their respective fuel injectors may result in excessive exhaust emissions and poor engine performance.

1. Drain the engine coolant from the cooling system. Refer to DRAINING AND FILLING COOLING SYSTEM .
2. Remove the throttle body air inlet duct.
3. Remove the accelerator control and cruise control cables with bracket from the throttle body.
   Fig 1: Identifying Upper Intake Manifold

   Courtesy of GENERAL MOTORS CORP.
4. Disconnect the wiring harness connectors from the following throttle body components:
   • Throttle Position (TP) sensor
   • Idle Air Control (IAC) valve
5. Disconnect the engine left side spark plug wires. Refer to SPARK PLUG WIRES .
6. Disconnect the engine left side spark plug wire harness attachment clip.
7. Disconnect the throttle body heater hoses. Refer to THROTTLE BODY HEATER HOSE REPLACEMENT - INLET or THROTTLE BODY HEATER HOSE REPLACEMENT - OUTLET .
8. Disconnect the vacuum hoses from the evaporative emission (EVAP) canister purge solenoid valve.
9. Remove the EVAP canister purge solenoid valve. Refer to EVAP CANISTER PURGE SOLENOID .
10. Remove the ignition coil bracket.
    Fig 2: Removing Ignition Coil Bracket

    Courtesy of GENERAL MOTORS CORP.
11. Disconnect the wiring harness from the manifold air pressure (MAP) sensor.
    Fig 3: Disconnecting Wiring Harness From Manifold Air Pressure Sensor

    Courtesy of GENERAL MOTORS CORP.
12. Disconnect the vacuum harness from the MAP sensor and the upper intake manifold.
    Fig 4: Disconnecting Vacuum Harness From MAP Sensor And Upper Intake Manifold

    Courtesy of GENERAL MOTORS CORP.
13. Disconnect and remove the emission control vacuum harness.
14. Disconnect the vacuum brake booster hose from the upper intake manifold.
15. Disconnect the vacuum hose connections from the upper intake manifold:
    • Heating, Ventilation and Air Conditioning (HVAC) vacuum source hose
    • Fuel pressure regulator
16. Remove the exhaust gas recirculation (EGR) valve. Refer to EGR VALVE .
17. Remove the MAP sensor and the bracket. Refer to MANIFOLD ABSOLUTE PRESSURE SENSOR .
18. Remove generator through bolt bracket.
    Fig 5: Removing Emission Control Vacuum Harness And Vacuum Brake Booster Hose

    Courtesy of GENERAL MOTORS CORP.
19. Remove the upper intake manifold studs and bolts.
    Fig 6: Removing Upper Intake Manifold Studs And Bolts

    Courtesy of GENERAL MOTORS CORP.
20. Remove the upper intake manifold.
    Fig 7: Removing Upper Intake Manifold

    Courtesy of GENERAL MOTORS CORP.
21. If replacing the intake manifold, remove the throttle body. Refer to THROTTLE BODY .
    Fig 8: Removing Throttle Body

    Courtesy of GENERAL MOTORS CORP.
22. Remove the upper intake manifold gasket.
23. Clean and inspect the upper intake manifold. Refer to INTAKE MANIFOLD CLEANING AND INSPECTION - UPPER  in the Engine Unit Repair Manual.
    Fig 9: Removing Upper Intake Manifold Gasket

    Courtesy of GENERAL MOTORS CORP.