Per the dash readout, I averaged 9.2mpg today from Byhalia, MS across Arkansas on I40, and just into Oklahoma to the rest area. 46k+ load of bottled water.
So far, I've driven a little over 750 miles on this tank of fuel (got the tune done immediately after filling up). All but 100 miles has been either with this load of water, or the previous load of brick which was just as heavy. 135 gallon tanks, still sitting just over 5/8 full.
Truck ran great across Arkansas. the hills west of Little Rock aren't huge, but never lost any speed on them.
I had them tune my truck about 18 months ago. I've been really happy. I run 70 all day long and I'm either full gross or MT and I average right around 7 for all miles. The biggest difference is the power. I usually run Midwest and stone SE. Only thing I've really noticed was the truck does run hotter ever since I did the tune. If I see it getting too hot, I back out of it a little or downshift. (I've got a Columbia glider with a 97 12.7)
Hope to get my fill ups all caught up in fuel gauges over the next couple of days.
Topped off this morning before getting my week started. 126 gallons. That got me from Effingham to Jonesboro, AR. There to Byhalia, MS. There to Muskogee. There to Claremore, OK. And from there to the house.
Delivered in Ozark, MO this morning. Reloading paper now in Harrison, AR and taking it to Twon Falls, ID. Should have time on this trip to get my fuel numbers caught up to my last fill up.