2012 Hesitation/Stumble on acceleration from a stop - MustangForums.com



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Old 11-05-2016, 09:18 PM   #1
WORKISSLOW
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Default 2012 Hesitation/Stumble on acceleration from a stop

I have the Steeda Intake and tune as well as the BBK TB. (MT)
I have this problem which comes and goes, When I let out the clutch it feels like the motor is stalling or misfiring or stumbling or starving or something.
I put new plugs in not that long ago (I have about almost 110k miles)

I put some fuel injector cleaner in (several times) and it seem to go away and then it came back.

I tried buying gas at different places, turn the Traction Control on and off..

The problem can go away for a month or two and them come back.

This last time it came back when I was sitting in heavy traffic on a hill and the problem seems to persist for several days after it starts.

It runs fine once it gets off the line. But there is noticeable hesitation and shuddering that comes and goes.

Sometimes I think the computer is getting thrown off when the weather warms up and I have to do a lot driving in heavy traffic, sometimes I think it might be related to letting the fuel level get low,,, but at this point this all seems like mind games.. I am going to check again tonight but so far it hasn't thrown any codes.
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Old 11-06-2016, 06:35 AM   #2
JJHoover
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return the car back to a stock tune and then reinstall your tune
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Old 11-06-2016, 08:38 PM   #3
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With a higher mileage car, one good thing to check is the fuel filter. I had a problem like that in a different car and that's all it was.

If you haven't replaced your PCV valve (or installed a catch can) yet, try that next. When they get sticky the car can become a little flaky too.

If neither of those help, try watching your air-fuel ratio if you have that gage in your cluster. If when it stumbles the AFR spikes high, the car is lean and not getting fuel. If it just sits there and stumbles it may be something in the spark or air flow.

Hope this helps!
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Old 11-28-2016, 06:03 PM   #4
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It was a dirty MAF sensor causing the problem, in hind sight I wish I had started there because it is just about the easiest thing to fix/clean.
I would imagine it was running lean sometimes but for some reason it never through a code and I don't have an A/F gauge, maybe it is time for a new toy?

Thanks for the help
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Old 11-29-2016, 09:21 PM   #5
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Glad you found it!

A dirty MAF would usually read low on air flow, so the car would inject less fuel, and therefore run lean of target. It may not have been running lean enough to throw a code, in which case you probably didn't toast anything. To be sure, pull a spark plug (number 5 or 6 is best) and look at it. If it looks cooked, it was lean!

No need to change toys unless ya just want to....and Christmas IS coming.
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Old 11-17-2017, 04:28 PM   #6
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I have a 2012 mustang V6. the hesitation is when I push him the car loss power for a second and them back to normal. is not always but. any one here experience the same?
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Old 12-05-2017, 01:49 PM   #7
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Hi,
I am new to all this Mustang stuff...I have always wanted a mustang convertible and I finally got a used one...here is my problem. I just bought a 2014 mustang V6 convertible and I absolutely love this car...I had to take it back to the dealer today to fix some minor cosmetic issues as they promised....well they gave me a 2014 v6 coupe to drive as a loaner car....the difference in this vehicle is nuts....the loaner car takes off a lot quicker with a hard acceleration and has no hesitation...my mustang hesitates for a few seconds before it takes off...I didn’t know any better because when I took mine for a test drive it hit the gas harder after I was already moving and the car got up at went...I was very impressed by the performance....but now that I’m using this loaner I can certainly notice the difference....I have been reading a lot of threads and it appears that this is a common problem that can be fixed by pulling #47 fuse and performance tuning...possibly just resetting the computer to adjust to my driving habits....

I don’t really want to mess with the car but I really want the ability to have the full performance out of my v6 like that of the loaner v6....any suggestions would greatly be appreciated.....do I need to pull the fuse to erase the driving habits of the previous owner?

thanks for all your advice...
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Old 12-05-2017, 05:22 PM   #8
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When you pull and replace fuse #47 you are resetting the memory so it isn't holding a learned driving pattern in memory. Perhaps the previous owner was a "cautious" driver so the car is using the "Keep Alive Memory" to drive slowly and carefully. The loaner car, like most rentals, has probably been driven much more spirited.

Pull the fuse, put it back and see what happens.

Tuning will definitely make a difference though.
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Old 12-05-2017, 07:53 PM   #9
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Thanks I will give this a try...
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Old 12-11-2017, 08:24 PM   #10
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Default no power gained

hi guys. I solve the coolant problem by replacing the water pump. after that I bought a CAI and a cat back mid pipe exhaust. the problem is my car is slower than with stock parts. the car sounds nice but the loss power is just sad and depressing. any advice?
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