Is there a way to recalibrate the speedometer? My GPS shows me going 75 while the speedo shows 79

 

what tire sizes are you using?

 

79 versus 75 is a big difference. Recheck your data.

 

The dealer I bought the car a few years ago from had on 23/55r17 so the speed was off by 1mph and I got new Michelin Pilot Sports AS3+ the other day. They only had 245/45r17 so that's what I went with. A little shorter than the 50 from OEM spec