Amazing MPG gains... Magic fuel, or ???

mi.drew wrote:
The road grader I use at work has a 101 gal. tank. The filling station we use has a very slight incline, almost level. If I fill up on one side of the pump then pull around to the other side of the pump so that I am facing the opposite direction, I can get almost 12 gal. more in it. A very small amount off level might be affecting more than you think.

That's an outstanding observation!!!

... And it may be related or similar to my practice of "trickle filling" our RV's fuel tank to get absolutely the most accurate and consistent amount into the tank at each fill up. That's why I don't completely trust mileage claims made by those who are basing their results on what they think are the keeping of "accurate" records from fuel-up amounts and odometer readings during RV trips.

IMHO, you probably shouldn't rely completely on the consistenty of the amounts of fuel that the gas pumps are putting into the tank at each fuel-up to compute gas mileage. That's because I think that the shut-off mechanisms of fuel fill nozzles (based maybe on vapor pressure?) may not be consistent from nozzle to nozzle. More consistency should be attained by force feeding a final small amount of fuel into the tank after the nozzle thinks it's time to shut itself off.