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    #1

    Bucking / Jerking

    Weird but lately while driving i been getting a strong "jerking" feeling only when coasting (lets say going 35/50 and letting of the gas pedal) i feel a strong bucking/jerking motion while it's slowing down but giving it gas it instantly stops bucking and drives smooth and idles just fine at lights or parked.. Today it was doing it i decided to throw it in Neutral while it was coasting and "jerking/bucking" & it stopped jerking? any ideas??
    It's weird because it's only when i let off the gas while driving
    Only thing this week i have done is Seafoam it (Vacuum line & added in gas) Messed around with timing & Changed the oil... No engine lights btw while it's happening.
    Last edited by extortion00; 12-07-2013, 02:31 AM.
    Tags: None
    #2
    I played around with timing again today before driving and still no difference "bucking" when letting off the gas so don't think timing has anything to do with it

    Comment

      #3
      Originally posted by extortion00 View Post
      Weird but lately while driving i been getting a strong "jerking" feeling only when coasting (lets say going 35/50 and letting of the gas pedal) i feel a strong bucking/jerking motion while it's slowing down but giving it gas it instantly stops bucking and drives smooth and idles just fine at lights or parked.. Today it was doing it i decided to throw it in Neutral while it was coasting and "jerking/bucking" & it stopped jerking? any ideas??
      It's weird because it's only when i let off the gas while driving
      Only thing this week i have done is Seafoam it (Vacuum line & added in gas) Messed around with timing & Changed the oil... No engine lights btw while it's happening.
      Check your tv cable connection at the throttle body. Also check your transmission fluid level and the condition of the fluid.

      Comment

        #4
        Fluid Looks/Smells Fine As Well As The TV Cable.. i recently just replaced the bushing with a brass one

        Comment

          #5
          Originally posted by extortion00 View Post
          Fluid Looks/Smells Fine As Well As The TV Cable.. i recently just replaced the bushing with a brass one
          It sounds like a tranny issue. Maybe the torque converter locking and unlocking when it shouldn't be.

          Comment

            #6
            Originally posted by mobydick View Post
            It sounds like a tranny issue. Maybe the torque converter locking and unlocking when it shouldn't be.
            No torque converter clutch in an AOD. 4th gear (OD) is "direct-drive," bypassing the torque converter entirely.

            extortion00, when you say this condition occurs between 35-50, I assume the trans is in 4th, not 3rd?
            RyPow
            1987 LTD Crown Victoria LX sedan - The "Sand Box" - 73K, towing package
            1987 LTD Crown Victoria LX Tutone Tudor - '96 Explorer 5.0 + 5spd swap in the works
            1985 Lincoln Town Car Cartier - previously owned by "navguy12" from thelincolnforum.net
            2007 Lincoln Town Car Signature Limited, 102k, daily driver
            2006 Mercury Grand Marquis LS, 115k, winter beats
            1977 Lincoln Continental Town Car, 42k
            2012 F-150 5.0L 4x4, HD payload pkg (towing/hauling)
            2015 Toyota RAV4 XLE AWD (better half's)

            Comment

              #7
              May not be a tranny issue at all. As you describe it, the bucking and jerking occurs during periods of high vacuum and a light engine load. All the normal vacuum operated "suspects" should be check out. I would start with all the hoses, then proceed to the EGR and other components that could lean the mixture during these high vacuum conditions.

              Comment

                #8
                it now seems to jerk around all speeds 20mph and up.. I've had this issue when i first got the car but it only happened when coasting around 5mph but went away on its own after about a week.. i will check hoses and egr first.. honestly though before it starts "bucking" while coasting at those speeds you can feel the transmission kinda downshift then it jerks
                Last edited by extortion00; 12-09-2013, 03:08 PM.

                Comment

                  #9
                  Originally posted by extortion00 View Post
                  it now seems to jerk around all speeds 20mph and up.. I've had this issue when i first got the car but it only happened when coasting around 5mph but went away on its own after about a week.. i will check hoses and egr first.. honestly though before it starts "bucking" while coasting at those speeds you can feel the transmission kinda downshift then it jerks
                  What year is it?

                  Comment

                    #10
                    89 5.0

                    Comment

                      #11
                      Check the charcoal canister and the plumbing to it. That mostly opens while coasting, and if there is a problem the engine can misfire. Any misfire is most obvious in third or fourth gear due to the bypassed torque converter. Most shudders and stuff like what you describe are not transmission problems, its usually an engine miss. The charcoal canister is under the battery and has 2 vacuum lines to it. Those are often in crap shape, and sometimes the canister cracks open. its purpose is to suck gas fumes out of the tank instead of just dumping them to atmosphere. A sticky EGR regulator can also cause this. Pull the vacuum lines from it and give it a quick snort of wd40 in both ports. Pull the cap off, clean the filter (if any of it is left) and give a bit of wd40 down the tube sticking up into the filter area. In general, check the vacuum lines, tuneup stuff, and fuel filter as well. It wouldn't be a terrible idea to check the U joints for binding either.
                      86 Lincoln Town Car (Galactica).
                      5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                      91 Lincoln Mark VII LSC grandpa spec white and cranberry

                      1984 Lincoln Continental TurboDiesel - rolls coal

                      Originally posted by phayzer5
                      I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                      Everything looks like voodoo if you don't understand how it works

                      Comment

                        #12
                        Where is the EGR located on the Marquis?

                        Comment

                          #13
                          The regulator lives on the passenger side fender. There are 3 vacuum solenoids over there. One by itself with a green and red line, and a pair side by side below. The single one with the red and green lines is the EGR regulator solenoid.
                          86 Lincoln Town Car (Galactica).
                          5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                          91 Lincoln Mark VII LSC grandpa spec white and cranberry

                          1984 Lincoln Continental TurboDiesel - rolls coal

                          Originally posted by phayzer5
                          I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                          Everything looks like voodoo if you don't understand how it works

                          Comment

                            #14
                            thank you i'll give everything a second look tomorrow

                            Comment

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