Had my first fuel-up (only a half tank from the 87 oct dealer probably put in) since picking up the truck last Saturday and I hit the 93 octane for sh** and giggles. Put about 90 miles on and it is now coming in avg 19.3 MPG. Up from 19.1 on the same mileage odo trip. Keep in mind I have not had a lot of city stop an go. I am in the sticks
. But I have also not hit a freeway averaging 70 mph either. I am b/w 60 mph max and just stop and go around rural towns between minimal hills/elevation. Since fuel prices are pretty good my plan is to deplete this fuel load as close to empty as possible and hit the 93 oct again and report my manual calculations to ya'll.