I thought I would let you guys know how my trip computers estimation of mpg is compared to what I calculated at my last two fill-ups. I reset the computer at both fill-ups as well. Both are a mix of city and highway.

#1 - computer 25.8 - calculated 25.9
#2 - computer 26.1 - calculated 25.7

It looks like my trip computer is doing a pretty good job. Have any of you guys made this comparison as well? If you know the numbers, please post so that we can compare results.

By the way, I now have ~1400 miles on the car. It feels so good to be done with the break-in, and the car sounds awesome in the higher rpm's.

 

I think yours is more accurate than most of ours, mine is usually off by a couple MPG's in both the 350 and Max.

 

It's probably about 75% highway.

 

My Z's trip computer usually reads 0-1 mpg (closer to 0.5) too high vs. calculated. It's better than my Max which usually read 2-3.5 mpg too high.