I think if I found a 500 mile hill with a constant tail wind, in neutral and the a/c off, I might hit that mileage.

Sad thing is that the diesels are close to that. We are close to getting low sulfur diesel fuel. I hear that's the reason we don't get them. I know of a few trucking companies that have test tanks and are doing studies. Keep your fingers crossed so maybe one day we can get them....

 

I wouldn't even get that just idling on a flat bed tow truck