How to Replace the Throttle Body in a GMC Sierraby Contributor
The GMC Sierra is popular among used-vehicle shoppers. Known more for its utility than its flash, the Sierra nonetheless offers handsome styling and easy handling. Between 1999 and 2006, the Sierra was available with 4.3L, 5.0L and 5.7L engines. This is an intermediate level do-it-yourself project for the removal and installation of the throttle body in those vehicles.
Remove the Throttle Body
Take the negative battery cable from the terminal. Remove the engine cover, then remove the air cleaner outlet resonator, the air cleaner outlet resonator adapter stud and the cable for the cruise control.
Loosen and remove the stud and nuts that hold the accelerator control cable bracket in place. Swing the bracket to the side.
Disconnect the idle air control (IAC) valve harness connector and the throttle position (TP) sensor harness connector. Take out the throttle body retaining studs.
Lift out the throttle body assembly. Discard the seal. Clean any gasket material and debris from the gasket surface of the intake manifold.
Install the Throttle Body
Set the throttle body assembly in place with a new seal. Place the retaining studs on the throttle body assembly and torque them to 80 inch pounds.
Install the studs for the air cleaner outlet resonator adapter. Tighten the studs to 71 inch pounds.
Connect the TP sensor harness connector, then reconnect the IAC valve harness connector.
Use the fasteners to install the accelerator control cable bracket. Torque the fasteners to 106 inch pounds.
Install both the accelrator cable and the speed control cable. Make sure that the neither of these cables holds the throttle open.
Put the air cleaner outlet resonator in place. Replace the engine cover. Connect the negative battery cable.
Depress the accelerator pedal to the floor, then release the pedal. Make sure that the accelerator pedal operates without binding between the full and close throttle.
- Place a clean shop cloth over the opening to the manifold to prevent dirt from falling into the engine.
Items you will need
- Mechanic's toolset, including a full socket set, wrenches, screwdrivers
- Torque wrench
- Replacement gasket
- Clean shop cloths
- Plastic scraper