2014 with 56K miles, bought the car new, never a problem really. I installed Ford performance shocks and struts and Steeda sway bars to mimic the performance handling package offered as an option to 2014. Now (years later) I get a vibration through the car usually at about 2000 rpms, when I'm at decel and there's some slack in the drivetrain. I'd say it's most pronounced when I'm running downhill at a pace where the engine breaking holds the car at speed, and the rpm's are around 2000. You can feel it in the wheel, in the shifter, in your seat... you can hear it, it rumbles. It happens if you depress the clutch at around 2000 rpms, just for a second you feel it. I can stop it by hitting the acel for just a quick jab. I brought it to the dealer, they spent hours on it, told me they think it's in the trany (6 speed standard shift), and they'd have to take the trany apart to know more. I called a transmission shop, they said they don't think it's in the trans, they'd take it for a day for test drives and put it on the lift. I called a drive train shop to ask if a 1 piece drive shaft might fix it. They said they doubt it's the drive shaft, and if I replace the 2 piece drive shaft with a 1 piece drive shaft it would set up a harmonic vibration that would make it worse (unless of course the problem is the driveshaft, which they don't believe it is- but they'll sell me a new driveshaft if I want one). So everyone agrees there's a vibration that occurs at around 2000 rpms when you lift off the gas, and continues as long as you're running around 2000 rpm, and it doesn't matter your speed or what gear you're in, and it goes away if you hit the gas, or coast down to below about 1500 rpm. But no one can tell me why. Sorry- has anyone experienced this? I'm at the end- I have no idea, and I think all the shops are guessing.