W 150 Pickup V6-239 3.9L (1991)
Throttle Body: Description and Operation
Throttle Body Assembly
The throttle body assembly is mounted on the intake manifold and houses the throttle plate, two fuel injectors, fuel pressure regulator, Throttle Position
Sensor (TPS), Idle Speed Control (ISC) actuator, and a Manifold Absolute Pressure (MAP) sensor.
Intake air flow is controlled by a cable operated throttle plate and by the position of the Idle Speed Control (ISC) actuator (when the throttle lever is at
the closed position). Engine idle speed is controlled by the ISC actuator and the ISC actuator is controlled by the engine controller. The throttle lever
rests against an adjustment screw at the end of the actuators plunger when the vehicle is idling. The ISC actuator is used to set throttle stop angle during