GPM

Anyone having issues all the sudden with GPM?
I just reached 70,000 miles and historically after filling up my miles per tank estimate was over 300.

all the sudden its down to 270.
And my average dropped from
21 highway to 17 at best.
Thoughts?
Thanks in advance

 

Gallons per mile?

only happens when you start running 45in tires, yeah you’ll get about 2 gallons per mile

 

Doesn't winter fuel mixes always drop fuel mileage?

 

I recommend you do a few manual "mpg" calculations to see where you are really at. The on board computer is doing what I would consider an estimate based on the conditions and parameters it can measure. Has something changed on your rig or how you drive it to affect its calculations? Maybe!

Having said all that, I find that my computer's determination of mpg is generally pretty accurate.