In central FL we have 89 ethanol free at Wawa. It is normally close to the price of premium, and my 7.3s love it performance wise and mpg wise. Definitely worth the extra cost to me.
I’ll have to try a tank. I get 13 overalll. Going 65 the other day through some mountains I got a little over 14.5 on the dash. Kicked it iup to 80 for the last 100 miles and some mountains and it dropped that 240 mile trip to 13.4. Mine is all stockJust the performance increase with the tuner was worth it for me. I hated how the truck would drag from a stop. Now, it will pick up quite well. When I was running stock tires, I could easily get 14.5 on the lieometer. I was showing about 460 miles per tank of gas. I changed to wider mud tires and took at pretty big hit on the MPG. I can get 13-13.5 if I am not in city driving. City driving kills the MPG. I am happy that I got the tune. I am still running the ethanol free even though I am paying over $5 a gallon for it.