I got 13.2 last tank,,, and I pulled a 3000pound 18foot travel trailer home on that tank

 

My last tank was 17.7, which is low for me, but I am building a bridge across a large wash(dry creek) and hauled a lot of rock around my property to build it. I have the standard 235/75/16, so no, it's not tire size throwing it off. I drive like there's an egg under the gas pedal and never exceed 55 mph-usually keep around 45-50 mph. I'm semi-retired and drive 90% on open highways, so it's slooooowwww and easy for me.

 

StarTron is a great product, use it on everything and just picked up a bottle at AutoZone.