K 2500 Truck 4WD V8-454 7.4L VIN J SFI (1997)
Throttle Body: Description and Operation
Locations
Description
The throttle body assembly is mounted on the intake manifold plenum, and is used to control air flow into the engine, thereby controlling engine output.
The throttle valve within the throttle body is opened by the driver through the accelerator controls. During engine idle, the throttle valve is almost closed,
and air flow control is handled by the Idle Air Control (IAC) valve.
The throttle body also provides the location for mounting the Throttle Position (TP) sensor and for sensing changes in engine vacuum due to throttle
valve position. Vacuum ports are located at, above, or below the throttle valve to generate vacuum signals needed by various components.