Loss of Acceleration & Hesitation

Discussion in '3rd Gen - 2007 - 2017' started by BluBlocker, Aug 7, 2019.

  1. BluBlocker

    BluBlocker Member

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    Hello,
    Thanks to all who respond to posts...I can usually search and find answers by reading responses. This situation is similar to other posts, but I have tried some fixes and no luck so far. My 2010 expedition (183,000 miles) has hesitation and loss of power. I am the second owner as of 101,000 miles and I don't believe the plugs/coils have ever been changed. While driving, sometimes it doesn't want to accelerate very well from a stop. It hick-ups and jerks. I have to pull off the accelerator and press again and sometimes again before it accelerates smoothly. Also while already driving (any speed) if I pull off the accelerator for a moment, and then back on it reacts the same way. I have noticed that if I pull off momentarily and the car seems to be "coasting" and I press on the gas again, it responds by jerking and weak/bogged acceleration. However, if I pull off and wait for "engine brake" where I can hear/feel the engine decelerating, and then I press on the gas again, it responds fine. The other symptom is that I can be out of drive (in 3rd. gear) at 4K or 5K rpm and it accelerates fine with normal acceleration. But the moment I mash the pedal and go WOT, it bogs and does not want to accelerate.
    I have changed all four oxygen sensors, both VVT solenoids, and the crankshaft position sensor. Last night I put a bottle of Techron fuel system cleaner to see if that helps. I checked to see if the oil from the K&N had migrated to the MAF, but it looked clean. Seems like an air or fuel problem, but could be spark?
    Thanks for reading...Thanks for responding!!
     
  2. Trainmaster

    Trainmaster Old School Member

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    Sounds exactly like a motor in need of new spark plugs. With 101K miles that's completely logical. Most of mine began misbehaving like that somewhere around 85K miles. They're shot at 100K for sure. I'll bet if you pull those plugs you'll find the electrodes eroded away to nothing.

    Change the plugs, fuel filter and air filter. While unrelated, it wouldn't hurt to change the transmission fluid too. Then you'll be up to date with maintenance and your problem will probably go away.

    The coils can last the life of the car. Don't change a coil unless it's giving you a Check Engine code.
     
  3. bloodhound

    bloodhound Full Access Members

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    183,000 on original plugs?? There you have it.
     
  4. BluBlocker

    BluBlocker Member

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    Thanks guys! I was thinking fuel, but spark plugs make sense. Hope it's plugs at least...that would be an inexpensive fix. I bought a fuel filter as well, but could not find it anywhere along the fuel line. I searched and someone said the 2010 was the first year of the flex fuel and they put it in the tank?
     
  5. 99WhiteC5Coupe

    99WhiteC5Coupe Full Access Members

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    Where did you buy a fuel filter that was indexed for your vehicle? Are you sure you have a serviceable fuel filter (not in the tank)? The online catalogs show the replaceable fuel filter from 2009 - 2012 for the flex fuel engine. I believe the filter may be under the car, near the frame rail - and a protective cover MAY have to be removed. Usually, it is on the left (driver) side, about 1/2 way back, under the second row seat area.
     
    Last edited: Aug 8, 2019
  6. BluBlocker

    BluBlocker Member

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    I looked up and down the fuel lines, but did not see it. I ordered the filter (Motorcraft FG-1036) through O'reilly's website. Might have to send it back if I can't find it or doesn't exist outside the tank...Thanks!
     
  7. Adieu

    Adieu Full Access Members

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    IMHO, there is no fuel filter on the flex fuel V8's

    That's a myth that keeps on getting requoted from one erroneous source

    Yep I bought one too and looked up and down my '09 for it. Even removed skid plates and stuff.... nothing I could find
     
  8. 1955moose

    1955moose Full Access Members

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    Do a fuel pressure test up front. If it's low, then considering changing the pump and filter. If the pressure is stable, you can eliminate the filter/pump. Basic diagnosis 101.

    Sent from my N9131 using Tapatalk
     
  9. montauksummer

    montauksummer Member

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    I have the exact same problem with my '07. I had the spark plugs changed for a 2nd time just before 200k miles. The job ($370) was done at a Ford dealership using Motorcraft plugs. Performance improved slightly but new plugs did not resolve the problem.
     
    Last edited: Aug 15, 2019
  10. Adieu

    Adieu Full Access Members

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    Afaik, once you get the break-ey 07-08 original plugs out the first time around, there's absolutely no need to spend $300 labor on a simple procedure the second time around
     

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