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F-150 Buck/Jerk at 50-60 mph

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  • F-150 Buck/Jerk at 50-60 mph

    Ditto. I just bought a 2001 F150 7700 4x4 BiFuel...AZ vehicle (30,000 mi) now in MI Ran great for the first few days on gasoline...like a dream. Then I was so exited to try running CNG I drove 30 minutes to the nearest FastFill location.

    It has been such a long time since they had a customer (MI) they filled me upfree and told me to try it out. Ran GREAT I even thought the throttle response was better. Next day, took it out for a drive in the rain stalled at a light dead while making a right turn and accelerating from a stop.

    Today took it for drive three on gasoline and it is bucking like a bronco right at 50 MPH and getting worse. Wierd how so many people are having problems.

    I am good with a wrench, but by no means capable of drilling out an engine block and tapping a new plug....please tell me this is not what I am facing for the rest of the life of this vehicle!

  • #2
    Re: F-150 Buck/Jerk at 50-60 mph

    Transmission control problem ? if it does this on gasoline.

    P.S. On the "Blown out spark plugs' all Ford v-8 and v-10 engines of the era were subject to the problem of stripped threads, unless carefully handled during plug changes. I think Ford re-designed the heads a few years back and no longer have the problem.
    Last edited by Lakewood90712; 12-26-2009, 12:22 PM.

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    • #3
      Re: F-150 Buck/Jerk at 50-60 mph

      If you ejected a spark plug, you would know it.



      Bucking is *usually* indicative of Coil Over Plug (COP) problems and/or plugs. I had an '02 F250 SuperDuty 5.4 that only stopped bucking after a full COP and plug swap. I saved some cash and bought my COPs off ebay for ~$100.00 for all eight and it ran great.

      Typically, the bucking will illuminate the MIL and give a code for the cylinder it thinks is causing the problems.

      Regarding a blown plug, Ford says to torque your plugs to ~14 ft/lbs, which is part of the problem coupled with the poor thread design in the head. The guys at blownoutsparkplug.com have safely torqued to over 100 ft/lbs and recommend a setting of 30 ft/lbs.


      ?Innovation is driven by having access to things.? -- Gleb Budman, CEO of backblaze.com

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      • #4
        Re: F-150 Buck/Jerk at 50-60 mph

        Had similar issue last week on my bi-fuel F-150 (2001) with less than 40k miles.
        (it all started after the heavy rain recently)
        The MIL came on and off (at least once I noticed) but did not stay on.
        I connected one of the cheap ODB readers and it returned a code P0301
        googling it returned a misfire on cylinder 1.
        After about a $370 repair (replacing coil and plug) my F-150 runs like a charm again.

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        • #5
          Re: F-150 Buck/Jerk at 50-60 mph

          Ive had the same occurrence on two '01 F150's. It may well be related to, or made worse, by another mechanical problem, but I think the normal problem is engine lugging (occurs because the ngas mixture setting is a little too lean to drive 55-60 in overdrive when the throttle at a low power setting or when the vehicle is climbing). I either give a little more fuel or shift out of OD and the problem goes away.

          I dont notice the lugging with gasoline, probably because it generates a bit more more power. Both seem to run well most the time, and are not generating codes.

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          • #6
            Re: F-150 Buck/Jerk at 50-60 mph

            Originally posted by OhMyGas View Post
            After about a $370 repair (replacing coil and plug) my F-150 runs like a charm again.
            ack! The #1 cylinder is the easiest one out of all them to get to! It's right up front.



            At most, if you did it yourself, it shouldn't have cost you more than $80.00. ~$65 - $75.00 for the COP and $3 - $5.00 for the sparkplug. Cheaper (as in price) can be found, but IIRC Autozone is around $65.00 or so ..


            ?Innovation is driven by having access to things.? -- Gleb Budman, CEO of backblaze.com

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            • #7
              Re: F-150 Buck/Jerk at 50-60 mph

              Can you post the part numbers of the plugs and coils? Is there a way to test the coil to see if it is good or not. If a couple are good I would like to keep spares and trash the weak ones

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              • #8
                Re: F-150 Buck/Jerk at 50-60 mph

                Originally posted by troach View Post
                Is there a way to test the coil to see if it is good or not.
                To my knowledge, the only conclusive way to test the coils is at the dealership. The inductive properties of the coils change with RPM and a coil may pass at idle and fail under load.


                ?Innovation is driven by having access to things.? -- Gleb Budman, CEO of backblaze.com

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                • #9
                  Re: F-150 Buck/Jerk at 50-60 mph

                  Hi Guys,
                  Well I have driven the vehicle a few more times and here is some more I have learned.

                  1.) I am only driving on gasoline.
                  2.) When my F150 "bucks" the "Theft" light blinks once for a millisecond during the buck.
                  3.) No Check Engine Light
                  4.) Read about the Ford Factory "PAT" theft system and learned it is completely integrated with every other sub system. But, when the PAT is triggered it shuts down the injectors and starter. Only PAT problems I could find were complete "it wont start" and the "Theft" light is blinking rapidly.
                  5.) Took to a Fleet Dealer today...only code was "P1640" - DTC's Available In Another Module.
                  6.) The said it is the "compuvalve"
                  7.) After reading all the other posts here...that is always the default answer....I was kindof miffed they did not check the other "modules" for a code.....

                  I suspect it has nothing to do with the compuvalve or the fact it a bi fuel...I bet it is something with the PAT system transponder, module...any thought by you guys would be much appreciated.

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                  • #10
                    Re: F-150 Buck/Jerk at 50-60 mph

                    Originally posted by RenewableEnergyFarmsLLC View Post
                    I suspect it has nothing to do with the compuvalve or the fact it a bi fuel...I bet it is something with the PAT system transponder, module...any thought by you guys would be much appreciated.
                    I would say there is a high degree of probability that the code is correct and that you should start troubleshooting the Compuvalve. PAT only prevents the engine from starting and those error codes start with a B.

                    There is an excellent thread on the dis/re assembly of the Compuvalve for cleaning in the Ford section of this forum.

                    Can somebody please make it a sticky?

                    Additionally, if you were to look at a Ford repair manual, it will stipulate that all driveablity issues be solved first in gasoline mode then CNG. Meaning, it needs to run great on gas before you try and figure out what is wrong with CNG.
                    Last edited by jblue; 12-29-2009, 11:28 PM.


                    ?Innovation is driven by having access to things.? -- Gleb Budman, CEO of backblaze.com

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                    • #11
                      Re: F-150 Buck/Jerk at 50-60 mph

                      Thanks JBlue,
                      My follow-up question is, why would a faulty compuvalve affect driving in gasoline mode?
                      T

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                      • #12
                        Re: F-150 Buck/Jerk at 50-60 mph

                        Originally posted by RenewableEnergyFarmsLLC View Post
                        My follow-up question is, why would a faulty compuvalve affect driving in gasoline mode?
                        The short answer is that it should not.

                        The PCM stores diagnostic codes as faults occur and they may or may not illuminate the MIL lamp on your dash. So this code may just be an artifact from something else. It is really anybodys guess at this particular point in time as to why it is there. There are only two ways to clear a stored fault code on a Ford:

                        a) disconnect the battery for several minutes.
                        b) use a scan tool like the one from autoenginuity.com

                        With that being said, first things first. Get your truck running top notch in gasoline mode and completely ignore that you can burn CNG for now.

                        btw, if your plugs have paint on the cap that touches the COP, you are holding a factory plug.


                        ?Innovation is driven by having access to things.? -- Gleb Budman, CEO of backblaze.com

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                        • #13
                          Re: F-150 Buck/Jerk at 50-60 mph

                          You need to install Motorcraft coils and Motorcraft natural gas spark plugs. I fought with this problem for two years--don't buy a new compuvalve.

                          Let me know if you would like any other information about this issue.

                          It would be nice if the moderators could merge this thread with the other of the same name.

                          Samuel
                          2001 F-150 5.4L Bi-fuel
                          7700 Extended Cab

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