I have not done any empty testing with it yet, loaned it out before I got to fill it and check it, they put some gas in and screwed up my numbers, so far the only solid numbers I have got was pulling an 8000LB skid steer one way on a 20ft deck over flatbed and a 1/2 ton 4x4 2011 ram the other way and got 11MPG so I was a little disapointed with that but the TQ pulling the big hills was very nice. It never triggered any knock sensor activity on the 89 octane I filled it with before I left.

On a side note I used it to haul a 500 gallon water tank when fighting the forest fire here and when the tank was full it only squated about 1/2 inch and still rode very stiff, parked next to a single wheel one ton 18 ram diesel and noticed someone has added thicker leafs than his truck has and air bags, I have no idea what they were doing with this truck but evidently something very heavy.