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Throttle Issues, anyone had this problem?

2K views 7 replies 7 participants last post by  Andre203 
#1 ·
Hey guys, I have a 2012 V6 Mustang with the performance package. A little over 35,000 miles. Only mod is a JLT CAI.

Lately it has something of a hesitation during hard acceleration, basically when you punch the gas, it accerates smoothly and sounds normal, until around 3-5k RPM...then all of a sudden the engine gets WAY louder than it used to, but without very much actual acceleration. Then the noise drops down, the acceleration picks up and then the noise will pick back up again when the variable valve timing kicks in again (5-6k RPM?).

It used to always accelerate smoothly, with a smooth sounding powerband. Now all of a sudden the engine roars out of nowhere, but without any real acceleration going on in the back end, and after 1-2k RPM it goes back to normal. My first thought was a slipping clutch, but the RPM's don't jump up when this happens, they climb gradually like they're supposed to.



This only really happens when you get on the gas, it doesn't happen if you're easy on the throttle. I'm no stranger to auto mechanics, but this one has me stumped, and all my mechanic friends stumped as well. The car is still covered under my extended warranty, and I'll probably make an appointment with the dealership soon, but I was wondering if anyone has had this issue before so I at least have an idea of what's wrong before I take it in.
 
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#3 ·
I mentioned that in the first post. The RPM's don't jump when I hear the noise, so I don't think it's the clutch.

Honestly we think it might be the variable valve timing kicking on at weird times. That, or it's something electronic. It's almost due for an oil change, but it's always had Motorcraft 5w-20 in it, straight from the stealership.

I know in my old Honda the VTEC would stop working if the oil got too low (the rings were shot) so I'm going to check the oil level just to be sure. It's only got 30,000 on it, but maybe it's low. I've been too busy the past couple months to check it as regularly as I normally do.
 
#4 ·
Do ECU reset/relearn then retest.
 
#5 ·
Hmm I actually recently noticed the same kind of thing happening too. I thought it may be the clutch slipping as well.. But I dunno. It's like what would happen when the traction control kicks in.. Hard to explain. Lemme know what you find out about this!
 
#6 ·
With Fords adaptive, "learning", transmission, it's been well discussed to do a "47 fuse pull". Basically fuse 47 in your fuse box in the engine bay, is the fuse that is for the power to that function of the engine/transmission. Pulling it and leaving it out for ten minutes will "reset" the process and supposedly your car will shift much firmer and overall drivability will be more crisp. I drive a 2010 F150, and since day one it's always drove with slight hesitation under aggressive throttle. A few weeks after I had the truck I thought I had a transmission issue, but soon found out it was fords power management system giving me what power the truck thought I needed, it is fords "learning" power management system, supposedly it "learns" your driving style/habits and adapts as it sees needed. This is what I've been told by other ford enthusiast and the local service dept.
This could be your issue, I'd try doing the fuse 47 pull!
 
#7 ·
May be a silly question but... Will this process help / work on a Manual Trans car as well?

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#8 ·
Are you still having this issue? This could also be related to the throttle position sensor or in our case the "drive by wire" throttle body. As far as the noise, have you looked at all the exhaust bolts to make sure they are tight? I would start from the headers and work my way back, just to make sure there is not a leak that occurs at a certain engine frequency or "RPM". Good luck.
 
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