Was that on a stock engine or did you have a tune??
I had a bama tune. After they rebuilt my engine they did a dyno to check the tune and everything was good. My car was just one of the ones that was built in the time that others were who had that problem.
2011 Mustang GT black. Mods: JLT CAI, JBA Long Tube Headers Catted H-pipe, GT500 axle back, Bama 93 Race tune, Koni STRTs, Speeda Sports, GT500 mounts, BMR LCAs, relo brackets and panhard bar