What Is a Throttle Body? The throttle body of your vehicle is basically a butterfly valve. The throttle body’s core function is to regulate and control the amount of air allowed to enter the engine. There is only one throttle body in most vehicles, with a rare exception of special, larger vehicles. The function of the throttle body is also dependent on other parts, such as the air filter. Bad Throttle Body Symptoms： Common symptoms of a failed throttle body include poor performance, rough idle, stalling and an illuminated check engine light. Part 1: Removing the throttle body .
