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94 Ford 302 high idle

Discussion in 'Ford Trucks' started by lockedandlowded, Dec 8, 2004.

  1. lockedandlowded

    lockedandlowded Junior Member
    from Texas
    Messages: 3

    I have a 1994 Ford F-150 with manuel trans and 302 v8. It has just started idling high. Once it reaches 2500 rpm it wont come back down unless you leave the engine off for a few min. Any suggestions?
     
  2. ksland

    ksland Senior Member
    from ma
    Messages: 420

    Most likely the Idle Air Control Selenoid, it is bolted to the top of the throttle body with 2 screws and a connector. Unbolt it and clean the carbon out of the plunger with fuel injection cleaner. If that doesn't work it may need replacing. Other than that it could be a vacuum leak in a hose somewhere. Please let us know what it was when you fix it for future lurkers answer.
     
  3. lockedandlowded

    lockedandlowded Junior Member
    from Texas
    Messages: 3

    Great thanks for the response, and I will try and let you know.
     
  4. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Could be the throttle position sensor too.
    A repair manual will have the testing procedure for it,you use a VOM to check it out. Or the butter fly may be sticking on the throttle also, make sure it is returning to the stop. <--Lube it with like WD40 etc.
     
  5. Midwest BuildIt Inc

    Midwest BuildIt Inc PlowSite.com Addict
    Messages: 1,280

    I once started my ford with the vacume line to the map sensor disconected and it just ran at about 2500 rpm. check the vacume line to the map sensor..you could have a leak.
     
  6. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    I had a GM truck do this years ago and it started suddenly too. It turned out to be a bad gasket leaking between TBI unit and manifold confusing the idle control valve.
     
  7. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    I worked for a Ford dealership for fifteen years, and found that the upper intake manifold gasket will get sucked in pretty simple to replace. I would look there first before replacing the Idle speed motor or TP sensor.
     
  8. JPMAKO

    JPMAKO Senior Member
    Messages: 660

    It could also be an Intake Manifold gasket leak.
    Spray some carb cleaner around the intake while the engine is running and if it gets sucked in and the engine starts to run rough than you know you have to change the gasket.


    Jason
     
  9. mylawn03

    mylawn03 Senior Member
    Messages: 229

    It was the IAC sensor in my 95 F-150 302
     
  10. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Most of the components that effects idle have test procedures listed in the emission control section in repair manuals. Don't be a "parts changer", because it will just upset you that the money was spent and it still idles high.
    If you can't afford multiple repair manuals go to the main library they have books going back 50 years.
    A scanning the CPU's memory may point you in the right direction, but don't hold your breath on that one.
     
  11. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    I was wrong most of the testing procedures is listed in the fuel system section of manuals. The last manual I used was for a Subaru. It had the stuff in the emissions section. But like I said test the stuff, better to test then replace good parts!(still save them as spares) Funny part is, I just had the same thing start!
    Turns out it was the idle air control,I had replaced it 4 years ago,must have been too much punishment! (or AutoZone part)
     
  12. lockedandlowded

    lockedandlowded Junior Member
    from Texas
    Messages: 3

    It was the throttle positioning sensor.
     
  13. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    My idles acting up too. The only problem is that it does it on the road and not in the driveway. ( engine warm or cold) I park it in the drive and drop the blade it idles fine! Put an extra IAC on that I had and the same thing happens. Guess I will just change the TPS and be done with it.