Located between the air filter box and the intake manifold, this component uses a butterfly valve to regulate airflow based on gas pedal input. In older systems, a physical cable pulls the valve open, while drive-by-wire setups use an electric motor controlled by the engine computer. A dirty or failing butterfly valve will cause a rough idle, stalling, or poor throttle response.
Grab some cleaner and a rag, the throttle body is caked with carbon and the butterfly is sticking.
Related terms
Intake manifold
The engine component that distributes incoming air or air-fuel mixture evenly to each cylinder.
Drive-by-wire
The replacement of traditional mechanical control linkages with electronic sensors and actuators.
Gas pedal
The foot-operated control that regulates the engine's power output and vehicle speed.
TBI
Throttle body injection is an early electronic fuel delivery system that sprays fuel centrally before the intake manifold.