Car encyclopedia

Throttle Body Service

The throttle body is a housing containing a valve(s) that regulates the airflow entering the intake manifold. Dirt and debris can built up on the throttle valve and the bore of the throttle body, restricting air flow when the throttle valve is closed.

Why Should It Be Serviced?

A dirty throttle body may affect engine performance, so it's important to have it serviced. If you don't, you may experience one or more of these symptoms:

  • Stalling and idling problems
  • Vehicle may not accelerate smoothly from a stop
  • Check Engine Light may illuminate
  • Gas pedal may become hard to push

When Should It Be Serviced?

  • We recommend a complete throttle body service every 30,000 miles. Having it serviced at these intervals will help reduce the chance of any related drivability concerns.
  • The throttle body should also be serviced if it becomes dirty. If the technician recommends this service, it may be possible for the technician to let you inspect the throttle body before it is cleaned.

How It's Done

When a throttle body is serviced, a technician cleans or wipes out the bore of the throttle body and the throttle blade itself using a special chemical solution. He/she then checks and adjusts the minimum air rate and throttle position sensor adjustment as necessary. The technician then performs a computer controlled idle relearn procedure. When this is all done properly, the vehicle should idle just like new.

Additional Notes

Throttle body service wasn't always so common. Carbon buildup on the throttle blade and in the throttle body has become an issue as the use of multi-port fuel injection systems has become almost universal. Before multi-port fuel injection, carburetors and throttle body injection systems delivered the fuel before the throttle blade. As the air/fuel mixture passed through the throttle body and around the throttle blade, it "washed" any carbon buildup before it could ever really begin. With modern fuel injection systems injecting the fuel after the throttle body, only air travels through the throttle body, so there is no fuel mixed with the air to keep the throttle body clean.

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