Air plays a vital role in enabling fuel combustion in your engine. And making sure your engine receives the right amount of air needed for combustion is your vehicle's throttle body. Now, this component is essentially comprised of a housing with an air valve inside. Like the rest of the valves in your car, the air valve is what controls airflow into your engine via its intake manifold. Depending on your vehicle's design, this particular valve will either be employed in MFI throttle bodies or TBI systems. MFI throttle bodies are basically used in multi-point fuel injection systems to regulate airflow. While in TBI systems or throttle body injection systems, this valve is also where fuel is shot through to make its way into the engine cylinders. In most engines, throttle bodies also come with the IAC (Idle Air Control) valve. This secondary circuit is what your vehicle uses to regulate airflow when your vehicle is idling. With a working IAC valve, stalling during idling is easily prevented. Aside from having slightly varying functions, throttle bodies can also differ according to their designs. Some of the predominant designs used today include butterfly valves, pinch valves, and barrel-type valves. To find out which type of throttle body your car uses, we recommend checking your owner's manual.