After having an airaid system installed and a Diablo Sport tuner installed on my 2013 mustang gt with 14800 miles I am left with a 10 mph off. I found this out when a very reputable shop replaced my 3.15 gears with a set of 3.55.Help please.

 

Is your Diablo Sport tuner a handheld device? There may be a way to adjust for the rear gear ratio change. If not, go to whoever uploaded the tune on your car and see if they can help.

 

Ya mess with Mother Nature............... (Ford), ya suffers the consequences. imp

 

...okay?