It can even cause your car to stall and effect the electronics of the car as well. Read on to find out how to tell if your throttle body needs a clean and how to clean throttle body. Before we delve into the complicated issues of sizing, spacing, and positioning involved with throttle bodies, we need to know what one is and how it works. Most standard production cars come with a single throttle body that controls the amount of air entering the engine. The butterfly opens and closes in correlation with the throttle position, and therefore allows more or less air to enter the engine. On a fuel-injected engine the throttle body is normally located between the air filter and the intake manifold, and is connected to the gas pedal mechanically with a cable, or electronically by wire. When the driver presses the pedal the butterfly in the throttle body pivots to let more air flow into the manifold. Yes, a bad throttle body can cause the engine to run rough or even not start at all. It is a component of the fuel injection system in your car, located between the air filter and the intake manifold. It’s responsible for regulating the flow of air into the engine.