Throttle Body Cleaning Tips

Is your car engine dying at slow speeds or at stops signs? Does the idle speed fluctuate up and down before the engine dies? These can be common symptoms of a dirty throttle body in need of cleaning. The throttle body basically regulates the fresh air flow coming into the engine from the air cleaner box. There is a vane/valve at the entrance to the throttle body which opens and closes with the accelerator position inside the vehicle.

Over time the vane or valve becomes gummy with dirty and varnish build up from gasoline vapors etc. This gumminess causes the vane to hang up and not close fully. This in turn changes the air flow going to the engine. The onboard computer sees this as a problem and tries to compensate the idle speed to make up for the loss of air flow. This causes an erratic idle sometimes referred to has hunting and pecking, since the tachometer gauge shows the RPM needle moving radically up and down trying to find a happy medium to keep the engine running.

In worst cases the idle speed can not be maintained and the engine dies, mostly at slow speeds and at stop signs with your foot on the brake in gear. Even shifting from forward to reverse can cause the engine to die.

What can you do to remedy the situation? Ask your mechanic to clean the throttle body with some gentle fuel injector cleaner and use a rag or tooth brush to remove the varnish and gummy build up inside and around the vane. This is a cheap and easy repair and can usually be done while you wait. We charge about $75 in my shop to do this, and it should be performed as regular maintenance about every 30,000 miles.

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7 Comments on "Throttle Body Cleaning Tips"

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  1. Milford says:

    My grandson told me he thinks I have a dirty throttle body and I think after watching your video he is correct. He is 21 and has some knowledge of cars should I let him try and do this?

    • Austin Davis says:

      Yes Milford, I would let him try it. Don’t think he can do any real damage. have him watch the video first though.

  2. Juan says:

    You guys made this look so easy. It was not really hard to clean myself but took me a little longer than what your mechanic friend did in the video. Thank you

  3. Tammie says:

    This was a very good explanation of the same problem I am having. Thank you very much Austin. You gave me the confidence to talk to my mechanic about the repair.

  4. April says:

    This was very helpful and describes perfectly what my car has been doing. I will defiantly have this done and hopefully have a fully functional car again. Thank you for the advice!

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