I have a 2002 7.3 with a DP TUNER set on 60 hp mountains. In perfect running condition with a ford ais intake and open exhaust and I get 16-17 mpg unloaded running 70 mph at 2100 rpm. With the toyhauler @14k fifth wheel and as aerodynamic and a brick I get 8-9 mpg @ 2400 rpm
The boat @5k is around 11-12 mpg @70 mph .the mpg would be much better if I kept the rpms under 2000 but. With out the chip is the same. I do not believe for one minute anyone is getting 30. I have know one person in the Real world to get 20 and this was a two wheel drive single cab with highway tires and manual trans .