06 GT Random Stalling Issue

Discussion in '2005+ Mustang GT 4.6L Tech' started by swflastang05, Oct 11, 2017.

  1. swflastang05

    swflastang05 Back for More

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    So a couple months ago I bought a 06 GT for my daughter to drive and it's been acting up lately where it will just randomly stall out on her while she's driving. Sometimes it happens while she's sitting at a red light and other times while she's driving down the road at 45+ mph. The CEL is usually not on, sometimes it does turn on but most of the time it's off. The only DTC codes it's ever displayed are p0053, p0054, p0059, and p0060, although just a few days ago there were no codes, and now there's only p0053 and p0059. I'm not sure if these codes are related to the stalling issue, I kind of doubt it though. The other issue the car has is the AC cycles on and off randomly sometimes, I think this might be related to the stalling issue. A little history is this car was leaking rain into the PS kick panel from the cowling cover gaskets, I recently sealed them all up and no more leaks. However that large harness plug in the PS kick got wet several times and had some corrosion. I cleaned it several times and at first it seemed to help but eventually it no longer made a difference. I ended up bypassing that plug by soldering wires across both sides so that should no longer be an issue. I've cleaned and tightened all the grounds, brand new battery, replaced the spark plugs (unrelated maintenance). The ignition switch seems to be okay, meaning I can pull on the harness and tap on it without any interruption but the problem still remains. It did it several times in a row idling in my driveway this afternoon. Usually it will start right back up after it stalls. The only weird thing is while idling with the AC running the rpms will sometimes drop real low for a second then spike back up, although sometimes it just stalls out. I've also tried cleaning the TB, checked all the harnesses and sensor wires to make sure they're all tight and found no issues.
    any suggestions? I'm pretty much shooting in the dark at this point. the car is 100% bone stock, the only thing aftermarket is a K&N filter in the OEM air box. Car has about 169k miles but runs strong when it's not stalling.
     
  2. Juice

    Juice forum member

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    All your codes are O2 sensor related. I can see that causing stalling while idling, but not driving down the road.

    Are you sure there are no codes stored? Any "pending" codes?

    To troubleshoot this, I would data log. (ford calls it flight recorder) And it would have to catch and record an event.
     
  3. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    Did you check the O2 sensor wiring harnesses? Sounds to me that you might have one of them shorting out somewhere causing the engine to run lean.
     
  4. 07gts197

    07gts197 forum member

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    The plug youre referring to, is it the smart junction box? That could be causing it to die. Otherwise my next thought would be crank position sensor but it should be throwing a code for loss of signal.
     
  5. AnotherS197GT

    AnotherS197GT Serial Valve Dropper

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    I think you probably have a grounding issue as well. You're getting codes for all the O2 sensors and they all share a common ground circuit. Something, somewhere is pinched or damaged. From the quick glance I took at the 3V PCM wiring diagram I have, only the O2 sensors are on that ground, which may be why you aren't getting any other codes. They do draw power from the same circuit as a lot of other critical engine sensors, so it's a little surprising you aren't seeing more codes.
     
    Last edited: Oct 12, 2017
  6. swflastang05

    swflastang05 Back for More

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    The problem is I don't have a tuner for this car since it's all 100% stock, I'm using an X3 from another car to pull the DTC's so data logging isn't really possible unless you can still data log without the tuner being married to the pcm?

    No I didn't really check them that well, I need to jack the car up nice and high and go through it really good, I'll do that this weekend when I have more time.

    No it's next to the SJB but not the SJB plugs, it's c210 I believe.

    Agreed, although I did redo all the grounds under the hood, ground down to nice clean bare metal on both the car and connector ends.

    I also read in another recent thread http://www.s197forum.com/forum/showthread.php?t=133170 where the two diodes in the bec were failing intermittently and that one of them is for the pcm and the other is for the ac clutch, both of which I'm having issues with. Maybe I'll swap them with a set from another car and see of that helps.
     
  7. swflastang05

    swflastang05 Back for More

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    After cleaning the MAF, replacing the pre-filter sock on the fuel pump and swapping the fuel pump relay I drove the car about 50 miles and it didn't stall one single time, although it did hiccup once while idling at a stop light so I'm going to replace the fuel pump just to seal the deal. I think the problem may be solved though.
     

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