when i got my 35 ft. cardinal 5th wheel i got 14.5 mpg on my 2008 chev 3500 dually 4x4. it did not change towing or not towing. now its dropped to 13.2. i changed fuel filter,air filter, no improvement. what can cause a drop in mpg? it is a diesal with allison automatic and 3.73 rear end. thanks.
Weight, Wind, hills, Sarting and stopping. Have you neen checking it with pen and paper or using the driver information center on the dash? That mpg seems pretty high. The best I get towing with less weight on mostly flat land and 60 mph is about 11.4-12.4.
With my 2011 Duromax, I notice a difference of up to about 1.5 mpg depending on where I buy my fuel. I'm not certain, but I suspect that it has something to do with the percentage of biodiesel in the blend.
2011 Silverado 2500HD Duramax, 4x4, crew cab, long bed
Palomino Puma 253-FBS, 27' 5th wheel
1994 19' Class B on Chevy chassis