I have noticed about the same thing... but with worse mpg's..
, but from what I understand it is just an error inherent in the gryphon... it was never designed to be 100% accurate in the readout of mpg's, only to give you an idea of what you are getting. My truck is also GPS accurate on the gryphon's speedo, and ive seen about a 2 mpg difference every time. I dont record them, but I check my mileage at almost every fillup, and its consistently the same amount low.
That's all I got, anyone else know any better than me?
