What is a throttle body?

A throttle body is part of the air intake system in a car that helps regulate the amount of air that passes into the engine to maintain the proper mixture of fuel and air. Typically the throttle body is located between the intake manifold and air filter box.

Within the throttle body is a large piece called the throttle plate that acts as a butterfly valve to regulate the airflow once the accelerator is pressed. When the throttle body does not work correctly, a driver notices a decrease in the car's performance, poor shifting of the transmission and improper idling. In addition, a decrease in engine power is often noticed.