GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC P42 Commercial Chassis 🢒 Engine 🢒 Engine Mechanical - 4.3L 🢒 Intake Manifold Replacement

Intake Manifold Replacement Upper

Removal Procedure
  1. Remove the PCV tube from the air cleaner outlet duct.
  2. Remove the air cleaner outlet duct from the throttle body assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.

    3. Object Number: 229041 Size: SH
  3. Disconnect the following electrical connectors:
    4. • The A/C pressure switch, if equipped
    • The throttle position (TP) sensor
    • The idle air control (IAC) motor
    • The fuel meter body assembly connector
    • The manifold absolute pressure (MAP) sensor
    • The EVAP canister purge solenoid valve
  4. Remove the EVAP canister purge solenoid valve. Refer to EVAP Canister Purge Solenoid Valve Replacement in Engine Controls.

    5. Object Number: 172995 Size: SH
  5. Disconnect the vacuum hose for the A/C system from the intake manifold.
  6. Remove the vacuum brake booster vacuum hose.
  7. Remove the PCV valve hose from the upper intake manifold.

    8. Object Number: 216754 Size: SH
  8. Disconnect the accelerator control cable from the throttle shaft.
  9. Disconnect the cruise control cable.

    10. Object Number: 398027 Size: SH
  10. Remove the nuts and the stud on the accelerator control cable bracket from the throttle body and the intake manifold.
  11. Remove the accelerator control cable from the throttle body and the intake manifold. Refer to Accelerator Controls Cable Replacement in Engine Controls.

    12. Object Number: 339442 Size: SH
  12. Remove the nut and the engine wiring harness bracket from the intake stud.
  13. Remove the fuel pipes from the fuel meter body assembly. Refer to Intake Manifold Disassemble .

    14. Object Number: 334513 Size: SH
  14. Remove the upper intake manifold. Refer to Intake Manifold Disassemble .
  15. Clean all sealing surfaces. Refer to Intake Manifold Cleaning and Inspection .

Installation Procedure

    Object Number: 334513 Size: SH
  1. Install the upper intake manifold. Refer to Intake Manifold Assemble .
  2. Install the fuel pipes to the fuel meter body assembly. Refer to Intake Manifold Assemble .
  3. Install the engine wiring harness bracket on the intake manifold.

    4. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  4. Install the engine wiring harness bracket nut.

    5. Tighten
    Tighten the engine wiring harness bracket nut to 12 N·m (106 lb in).


    Object Number: 398027 Size: SH
  5. Install the accelerator control cable bracket to the throttle body and the intake manifold.
  6. Install the stud and the nuts to the accelerator control cable bracket.

    7. Tighten
    Tighten the bracket stud and the nuts to 12 N·m (106 lb in).


    Object Number: 216754 Size: SH
  7. Install the cruise control cable, if equipped.
  8. Install the accelerator control cable to the throttle shaft. Refer to Accelerator Controls Cable Replacement in Engine Controls.
  9. Install the EVAP canister purge solenoid valve. Refer toEVAP Canister Purge Solenoid Valve Replacement in Engine Controls.

    10. Object Number: 172995 Size: SH
  10. Connect the PCV valve hose to the upper intake manifold.
  11. Connect the vacuum hose for the A/C system to the intake manifold.
  12. Install the vacuum brake booster hose.

    13. Object Number: 229041 Size: SH
  13. Connect the following electrical connectors:
    14. • The A/C pressure switch, if equipped
    • The throttle position (TP) sensor
    • The idle air control (IAC) motor
    • The fuel meter body assembly
    • The EVAP canister purge solenoid valve
    • The manifold absolute pressure (MAP) sensor
  14. Install the air cleaner outlet duct to the throttle body assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  15. Connect the PCV tube to the air cleaner outlet duct.

Intake Manifold Replacement Lower

Removal Procedure

    Caution: Before servicing any electrical component, the ignition and start switch must be in the OFF or LOCK position and all electrical loads must be OFF, unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal, also disconnect the negative battery cable. Failure to follow these precautions may cause personal injury and/or damage to the vehicle or its components.

  1. Disconnect the battery negative cable.
  2. Remove the PCV tube from the air cleaner outlet duct.
  3. Remove the air cleaner outlet duct from the throttle body. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  4. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.

    5. Object Number: 34397 Size: SH
  5. Remove the distributor. Refer to Distributor Replacement in Engine Electrical.
  6. Remove the radiator inlet hose at the water outlet.
  7. Remove the heater hose from the intake manifold.
  8. Remove the water pump inlet hose from the intake manifold.

    9. Object Number: 216754 Size: SH
  9. Remove the accelerator control cable from the throttle shaft. Refer to Accelerator Controls Cable Replacement in Engine Controls.
  10. Disconnect the cruise control cable, if equipped. Refer to Cruise Control Cable Replacement in Cruise Control.

    11. Object Number: 229077 Size: SH
  11. Disconnect the following electrical connectors:
    12. • The fuel meter body assembly
    • The EVAP canister purge solenoid valve
    • The A/C compressor high pressure switch
    • The A/C clutch switch
    • The ignition coil
    • The ignition control module (ICM)
    • The idle air control (IAC) motor
    • The throttle position (TP) sensor
    • The exhaust gas recirculation (EGR) valve
    • The engine coolant temperature (ECT) sensor
  12. Remove the engine wire harness from the retainers.
  13. Move the engine wire harness aside.

    14. Object Number: 172982 Size: SH
  14. Remove the inlet pipe and the clamp bolt from the exhaust gas recirculation valve (EGR).
  15. Disconnect the fuel pipes at the rear of the intake manifold.
  16. Disconnect the vacuum hose for the A/C system from the intake manifold.
  17. Disconnect the vacuum brake booster hose from the intake manifold.

    18. Object Number: 172995 Size: SH
  18. Disconnect the PCV hose from the intake manifold.
  19. Remove the purge solenoid valve studs from the EVAP canister.
  20. Remove the purge solenoid valve from the EVAP canister.
  21. Remove the fuel pipes from the rear of the intake manifold.

    22. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.


    Object Number: 340090 Size: SH

    Important: Do not discharge the A/C refrigerant.

  22. Perform the following in order to remove the left front bolt from the intake manifold:
    23. 22.1. Remove the drive belt. Refer to Drive Belt Replacement .
    22.2. Loosen the nut for the power steering pump rear bracket at the side of the engine.
    22.3. Remove the rear bracket nut for the power steering pump at the front of the engine.
    22.4. Remove the bolts and the nut for the power steering pump bracket.
    22.5. Leave the A/C compressor and power steering pump on the power steering pump bracket.
    22.6. Slide the power steering pump bracket forward in order to access the bolt at the front of the intake manifold.

    Object Number: 31510 Size: SH
  23. Remove the lower intake manifold. Refer to Intake Manifold Removal .
  24. Clean all sealing surfaces. Refer to Cylinder Head Cleaning and Inspection and Intake Manifold Cleaning and Inspection .

Installation Procedure

    Object Number: 31510 Size: SH

    Notice: Proper lower intake manifold fastener tightening sequence and torque is critical. Always follow the tightening sequence, and torque the intake manifold bolts using the 3 step method. Failing to do so may distort the crankshaft bearing bore alignment and cause damage to the crankshaft bearings.

  1. Install the lower intake manifold. Refer to Intake Manifold Installation .
  2. Transfer parts to the new lower intake manifold. Refer to Intake Manifold Disassemble and Intake Manifold Assemble .

    3. Object Number: 340090 Size: SH
  3. Position the power steering pump bracket.
  4. Loosely install the power steering pump bracket bolts and the nuts.

    5. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  5. Install the nut for the power steering pump rear bracket at the front of the engine.

    6. Tighten
    Tighten the bolts and the nuts to 41 N·m (30 lb ft).

  6. Install the drive belt. Refer to Drive Belt Replacement .

    7. Object Number: 172995 Size: SH
  7. Install the PCV hose to the intake manifold.
  8. Connect the vacuum brake booster hose to the intake manifold.
  9. Connect the vacuum hose for the A/C system to the intake manifold.
  10. Install EVAP canister purge solenoid valve. Refer toEVAP Canister Purge Solenoid Valve Replacement in Engine Controls.
  11. Install the fuel pipes to the rear of the intake manifold. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.

    12. Object Number: 172982 Size: SH
  12. Install the inlet pipe clamp bolt to the exhaust gas recirculation (EGR).

    13. Tighten

    1. Tighten nut to 25 N·m (18 lb ft).
    2. Tighten the EGR valve inlet pipe exhaust manifold nut to 30 N·m (22 lb ft).
    3. Tighten the EGR valve inlet pipe clamp bolt to 25 N·m (18 lb ft).

    Object Number: 334551 Size: SH

    Important: In order to install the distributor with the correct engine timing, position the engine to number one cylinder to top dead center.

  13. Remove the spark plug from the number one cylinder.
  14. Rotate the crankshaft until the number one cylinder is in the compression stroke.
  15. Align the 2 reference marks on the crankshaft balancer (1) and (4) with the 2 alignment marks (2) and (3) on the front cover.
  16. Install the spark plug in the number one cylinder. Refer to Spark Plug Replacement in Engine Electrical.
  17. Install the distributor. Refer to Distributor Replacement in Engine Electrical.

    18. Object Number: 229077 Size: SH
  18. Position the engine wiring harness.
  19. Install the engine wiring harness in the retainers.
  20. Connect the following electrical connectors:
    21. • The fuel meter body assembly
    • The EVAP canister purge solenoid valve
    • The A/C compressor high pressure switch
    • The A/C clutch switch
    • The ignition coil
    • The ignition control module (ICM)
    • The idle air control (IAC) motor
    • The throttle position (TP) sensor
    • The exhaust gas recirculation (EGR) valve
    • The engine coolant temperature (ECT) sensor

    Object Number: 216754 Size: SH
  21. Install the accelerator control cable and the bracket to the throttle shaft. Refer to Accelerator Controls Cable Replacement in Engine Controls.
  22. Install the cruise control cable, if equipped. Refer to Cruise Control Cable Replacement in Cruise Control.
  23. Install the water pump inlet hose to the intake manifold.
  24. Install the heater hose to the intake manifold.
  25. Install the radiator inlet hose to the water outlet.
  26. Install the air cleaner outlet duct to the throttle body. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  27. Connect the PCV tube to the air cleaner outlet duct.
  28. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  29. Connect the battery negative cable. Refer to Battery Cable Replacement in Engine Electrical.