Winter fuel now. Whatever that is. Empty truck Winter fuel treatment.Total Power it’s called. On level ground sea level 55-60 -65 miles per hour the dash thing says 18.5 sometimes . Getting maybe a solid 2.5 mpg increase no wind. In traffic 15.5 -16.0. Truck is broke in now 12 k I can live with the fuel mileage . I think the fuel additive is the improvement but who knows