Ford Mustang Forum banner

2012 GT automatic not downshifting

3K views 32 replies 9 participants last post by  2012GT95MkVIII 
#1 ·
My car has 50,000 miles on it and has had the Bama 93R tune for 25,000 of those. Lately I've been having an issue where when say merging into traffic and I put the hammer down the car will downshift but not accelerate. It's like it just stonewalled at 5,000 Rpms. I can hold it to the floor and it absolutely does nothing after that. Let up and it feels stuck in 3rd then will shift hard and act normal until I floor it again and same issue. Drive it a few miles and it disappears, turn it off and back on and the issue disappears. I can usually tell if it's going to happen before it does. Like today I was playing a lil and every time I punched it there was a delay then the car would downshift and takeoff til it didn't. Cut it off and it was back to itself again. I've pulled fuse 47 and saw no difference, reloaded the tune and ditto. Just put in the 93p tune and haven't tried that out yet. I'm wondering if i the tune(after 25,000 miles?) or if it's a tcm voltage issue. Any ideas?
 
#2 ·
I'd say try the other tune first. You should also be able to change your shift points with the tuner and see if the behavior is the same.
 
#3 ·
Change back to stock and see if it still occurs.
 
#5 ·
Pretty sure I don't have the stock tune anymore. I do have a backup tune in the Diablo tuner that may be stock, I'd have to install to find out. Also I said it doesn't downshift, it does but then stonewalls as described like it's not sure if it's okay to downshift or not. Strange it would occur now. I've heard of the batteries causing similar issues so that may be my next stop if it still occurs.
 
#6 ·
Hey 2012,

Although it is extremely uncommon for something to occur that long after a car is tuned and be directly related to the tune, I would still love to look into this for you.

Shoot me over a PM with your order # and I will have Bama's lead calibrator reach out to you personally and get to the bottom of this!

Hope this helps and looking forward to hearing back.

-Will
 
#7 ·
It has done it before but it was only occasionally.
Now it's every other day. I did change tire sizes since the tune but it's nothing extreme. I've had short shift issues on the 1-2 upshift since the beginning and I just drove the 93p and had no issues. Yet.... Although compared to the R the P is mush. To be fair most of those 25,000 were racked up on 2,000 mile road trips, not daily driving like I am now. If the 93p does fine again tomorrow I'll shoot ya a pm.
 
#11 ·
Same issue with the 93p tune. It seems to happen within a few miles of leaving after the car has sat 4+ hours or on long trips. That being said I'm having the battery tested now.
 
#14 ·
In the video you can see the RPMs up and then dropping as the transmission shifts. The video started right after it had done what I described above. I then punched it and you can see the result. It's like it commanded a downshift but then decided the speed was too high for that shift and stopped the power til 3rd engaged. I have the stock tune in now so we'll see.
 
#16 ·
Probably going way outside the box here as it seems most feel it is probably tune related but since you have tried various tunes and resetting to stock, could it possibly be transmission related? Wishing you the best of luck with resolving this as it sounds really frustrating!
 
#17 ·
I don't think it's the transmission itself since turning it off and back on instantly resolves the issue. Obviously it's not the tune since it's doing the same thing on the stock tune. I'm thinking it may be an issue with the TCM. Manually shifting it's fine, hill assist on it's fine, in D it acts up. It's like it allows the downshift into 2nd but then decides it doesn't want to be in 2nd. And really and truly judging how high the RPMS are when it dropped into 2nd it shouldn't have commanded a downshift into 2. Still questioning if it may be a voltage issue after the battery has sat since this mostly happens within 5mins of leaving. I may let it idle for 10 minutes or so before leaving work to see if it still happens.
 
#18 ·
Update: I let it idle for 5 minutes after work before leaving. During that 5 minutes I found a post on here about calibrating the gas pedal. Did the calibration process and the issue hasn't occurred since.
 
#19 ·
I'd give it a couple of days, but please provide the link in case this happens to someone else.
 
#20 ·
I have a Diablo in tunerwith bama tunes and I had the street tune installed for several months and mine did the same thing. Intermittently then more often then every other day. So I reloaded my stock tune and after 50 or so miles it has not happened since. Over two months and it's fine. I also had a harsh shift from first to second in slow traffic that was always there.
It's the tune!!
 
#22 ·
No, it has not happened once since I reloaded the stock tune.
 
#23 ·
Also I have not reloaded the bama tune because even if the problem of not downshifting was better it still would have that harsh shift from first to second in slow traffic. Thinking about selling my Diablo intune.
 
#24 ·
My did it once with the stock tune but hasn't since. I'm reloading the Bama tune now to see if it was the tune or a gas pedal calibration. I agree with you on the 1-2 shift. It's pretty hard at low speeds. If mine acts up again I'll be going with a new tuner. Probably Steeda or Lund.
 
#26 ·
They never got the 1-2 shift RPM right and my last revised tunes were awful. I like AM but I think as far as my tune goes I'll shop around especially since now we all know what caused the #8 issue and I'm outside of the Bama tunes 36,000 mile warranty.
 
#27 ·
Exactly what my car would do with Bama tune. AM spent MONTHs trying to fix it. They never could. WHen my wife almost got plowed by a semi getting on the highway because it did this merging on the freeway, we had to get it fixed. Very first revision of Mike Rousch tune fixed it, never done it again. Shifts so much better, no issues. Bama tried and tried but couldn't fix it.

Best of luck, but I would just get a different tune. Not only will it fix it, it will be safer and make more power in my experience.
 
#28 ·
Well it's official..... The Bama tune is the issue. Uploaded the 93R tune and now I'm back to inconsistent throttle response which means it's just a matter of time til it starts the downshift issue again. Now I just need to decide which tuner to go with.
 
#33 ·
Right now I'm just happy that the car is back to it's old self. I haven't tried any of their new tunes because well frankly because the last ones sucked. The 93H they sent was a joke. I may look into the new ones. Thanks for the info about em.
 
#32 ·
After a few miles the Bama tune is back to performing like it did when I first installed it on day one. I can only speculate that the issue occurred with the R tune since it is "race" tune and it's been being used in a daily driver. But mine is coming off daily driver duty soon as I get my sable up and going again. We'll see how the tune continues to go but soon as I get some free cash or find a new tuner who writes Diablo tunes, I will be testing the market. So if you're reading this and having the same issue, it's the tune.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top