MPG Cruising on Interstates at 75, 70, 65?

I just had a trip to Trenton NJ from Buffalo Ny and back. Two fill ups, a bit over 900 miles, average speed said 58 (highway speed was well over 75 but under 85) average MPG lists as 47.3

Most all the way back from Trenton was spent in power mode.

 

power mode makes no difference in this situation .. ... it is just remapping you gas pedal input ... (and a few other things like auto A/C and warm up cycle ...)

So your drive shows the car cp is EXCELLENT ... that is it and of course lower your speed better MPG you would get (at to some point of course)

 

Geez, it sure does look like that somebody doesn't like bathtime!
900 miles is a long trip - did you have coffee intravenously pumped into your body?

 

900 miles round trip, it was a two day meeting, lots of coffee and almost every rest stop