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Throttle stays open

Discussion in 'Air Intake, Engine Electronics, Ignition & Exhaust' started by ShadowLord, Nov 4, 2017.

  1. ShadowLord

    ShadowLord Member

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    I have a 1996 Ford F-150 4.9L E4OD. My throttle stays open when I change gears/accelerate hard/or when I'm going down hill, foot off gas-for a few seconds after I let my foot off the gas. If going down hill it will randomly act as though I'm tapping the gas pedal. It accelerates, then engine brakes, then accelerates again if im going down hill. Sometimes it even just stays throttled open. I have replaced the IACV last weekend. TPS was changed last year. I cleaned the throttle body last weekend, it helped a little bit but not much. No visible vacuum leaks that I can see or any hissing.
  2. Action

    Action Moderator Staff Member Respected Member

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    In no particular order and some of these with throw a OBD II code

    Injectors dumping fuel when they should be nearly closed
    Throttle body is worn and throttle is not closing smoothly
    Vacuum leak(s) or unmetered air getting past throttle body
    TP sensor is bad, again.
    MAP sensor is not working or disconnected. Not getting high vacuum signal to processor.

    >>>>>>>>>>>>Action
  3. ShadowLord

    ShadowLord Member

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    How would I check to see if the throttle is not closing properly/worn? When I opened it up to clean it, it seemed to close all the way?
  4. Action

    Action Moderator Staff Member Respected Member

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    With the air intake off.......Take springs or tension off of throttle.

    With a flash light look into the throttle body and operate the throttle shaft. You are looking for smooth operation and the throttle plate closing nearly all the way.

    Engine running you can carefully spray carb cleaner at the throttle shaft ends. If the rpm changes you have a leak there.

    >>>>>>>>>Action
    Last edited: Nov 4, 2017

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