[E. Pluribus Unum]

I have actually tried it both ways a number of times under the same exact circumstances and have empirically determined that putting the tailgate down to increase gas mileage (about 10%) is not a myth.

How many times have you tried it?

Or do you just have a religious belief in whatever expert you happen to be quoting at the moment?

[Red_Devil 232]

If it makes you feel good just leave it down.

I don't suppose you might have thought that the truck manufactures have tested this and if it did increase gas mileage by "any" amount they would use that fact when stating fuel economy ratings. There would be a section on this in their "Owners Manual" titled - Leave Your Tailgate Down For Better Mileage.

You can bet I will not be quoting your 10% self perceived increase in fuel economy!