Idle Speed/Throttle Actuator - Mechanical: Description and Operation

The throttle opener is located on the front of the throttle body and helps control the idle speed with the engine running. When vacuum is applied to the throttle opener (engine running), it reacts and allows the throttle lever to move and lower the engine idle speed. When the engine is first started, the throttle opener is fully extended, therefore the throttle lever and valve are opened a little, thus increasing the engine idle speed.