I have a 2012 v6 Mustang
w/ PP. It has approx. 35,000 miles on it, very nice condition, well cared for.
Recently, it started having some odd driveability conditions. It seems to do a few weird things, not necessarily at the same time.
1. The variable valve timing (Ford vtec) will kick in at odd times, sometimes as early as 3,000rpm when at WOT (wide-open throttle). Usually this happens when the car is under load, like on a steep hill and I punch the gas, but it happens at other times as well, and at other rpm's. In my old Honda, vtec kicked in at the same rpm every time. I'm not sure if the version of variable valve timing in my mustang is similar, or if the ECU is choosing when to engage it based on demand and this is normal.
2. Sometimes I will be on the throttle with my foot in the same position, and while it's accelerating, the engine rpm and the amount of acceleration I feel will stall, then it will pick up again a second or two later. Kinda like a sticking throttle plate or something.
3. Sometimes when under hard acceleration, especially at lower rpms at WOT) the engine will get louder, as it should, but without the accompanying push of acceleration. Almost like a clutch slipping scenario, but not quite. Often this happens when the variable valve timing kicks in early.
I took the stang over to my mechanic buddy so he could test drive it, and neither of us really know what to make of it. His best guess was that it sounds like a computer issue, that maybe it needs a software update or the ECU reflashed. I can't find any relevant TSB's though, although I have yet to call Ford and ask if there are any software updates needed for my model year.
So, has anyone else had any of this happen in your Mustangs?