01 Mustang Gt Jerks/bucks

Discussion in 'SN95 4.6L Mustang Tech' started by StangGal76, Sep 22, 2013.


  1. StangGal76

    StangGal76 New Member

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    Automatic/62,000 miles- When I'm doing 45 or higher and let off the gas, the car will jerk.

    Battery was recently disconnected while installing new radio. Has done this jerking while going through the relearn in the past, but this time its taking longer.

    I changed the fuel filter last nite and it was dirty. I disconnected the battery again before taking it out today, but it's still doing it.

    Any thoughts/ideas?
     

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  2. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor
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    Does it chop up at idle at all?
    Have you pulled codes on it yet?
     
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  3. StangGal76

    StangGal76 New Member

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    Idles fine.

    Check engine light always on cuz of h-pipes. Guess I will go to Autozone tomm to see if its throwing a new code.
     
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  4. 1987stangman

    1987stangman Member

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    I've owned 2 4.6l Mustangs and I have had to disconnect the battery severel million times for one reason or another and never had a bucking or jerking issue until PCM learned what it needed to. I would have been concerned about it right off the bat when it started. I recently ran into a COP that was failing and would miss the worst during WOT shifts that would make the car buck after the shift. like said above, get the codes read cuz it could be a million things. IMO everyone that owns a Mustang should have a code scanner. Even if you do not do your own work it could save a person some extra cash on what could be a simple repair.
     
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  5. wmburns

    SN Certified Technician

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    Might be handy to include the model year of your Mustang.

    +1 on checking for any outstanding DTC codes.

    +1 on checking the basic "tune up" items. The number one reason for buck/jerking is ignition related. #2 is EGR.

    IMO, you should consider the possibility that the automatic lock-up torque converter lock/release as the cause for the jerk. This is based upon the OP's original description. IE it only happens at higher speed at WOT when releasing the throttle.

    What is the condition and level of the automatic transmission fluid? Correct level? Bright red or brown?

    Tell us about the "other" mods. For example, do you have the IAC restrictor installed to "fix" the hanging idle? If so, this could be part of the problem.

    As for the time it takes for the PCM to re-learn after a battery disconnect, some cars take more time than others. The process begins again at each battery disconnect. A weak battery can extend the re-leaning time.
     
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  6. ForgedBlack01gt

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    Bucking at 45 has ALWAYS happened with my stang at 45mph. Different trannies, tunes, etc.

    Keep your car in OverDrive off until about 60 and you wont see problem I think. Car is fighting itself whether it wants to be in 3rd or 4th gear... Owned my car since new and there used to be a TON of posts about this...

    OD off keeps it out of 4th gear... usually a 40-50mph issue when cruising right? If you install gears then the MPH changes also but no clue what to since not gone down that road...
     
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    Last edited: Nov 11, 2013
  7. Decipha

    Decipha Member

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    x2, there is a slight gear scheduling overlap issue on some of the 01 and 02 calibrations

    nothing that cant be fixed by a knowledgeable tuner

    also have u tried adjusting the throttle body stop?

    if u have an aftermarket bypass on there take it off, when the engine gets up to warm operating temp in neutral unplug the tps and iac sensors, open the throttle body stop until the engine idles around 650-700 rpm, then shut it off, plug both connectors back in and fire it back up, dont worry about the flare up on crank, the airmass correction will be maxed and work its way back down where it should be
     
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