I have an 04.5 Cummins. 4x4, auto, 5" straight pipe with FTE resonator and 285/75/17s. Everything else is stock.
Most of my drivings 20 miles round trip and avg. 100 miles per week pulling xb2003. I avg 14.5-16 depending if I take hilly route.
Without pulling boat 17-18mpg.
That's...