For: 1997-2003 Ford F-150 (4.6L and 5.4L Only) 1997-2003 Ford Expedition (4.6L and 5.4L Only) 1999-2003 Ford F-250 Super Duty (5.4L Only) 1999-2003 Ford F-350 Super Duty (5.4L Only) About the Throttle Body: The throttle body is an important part of the intake system, controlling the amount of air that flows into the engine, which then burns the fuel in the cylinders. It is important to let the right amount of air in at all times in order for the engine to run at its best. When the throttle body becomes messy, faulty, or clogged, it blocks the flow of air into the engine, causing performance issues, and allows unburned fuel to pass through the exhaust system. .
