Air Induction
Filtered air from the air cleaner enters the intake manifold through the throttle body. The idle speed stepper motor is attached to the throttle body and controls the amount of air allowed through throttle body at idle. A manually operated throttle valve (operated by accelerator cable) controls the amount of air allowed through the throttle body above idle. The throttle position sensor (TPS) is also mounted on the throttle body and is connected to the throttle valve shaft. See Fig 1 . There are different throttle bodies for automatic and manual transmissions. The ECU does not control throttle valve.