I'm way out of it with wrenching but this is throwing me. When i bought the truck w/73k mi it'd get 25mgp at 85 mph @ 2500 rpm. & 15-18 in town.
this is a dually, 4x4 stick, did the DPF, delete, unplugged the EGR & Throttle valve. I pull a 38 ft 5th whl full-time, & have a 400cc motorcycle on the front. (I'm in level Amarillo Texas headed to Arizona) getting 9mpg, running hot and am so confused. electronic thermostats & e-clutch fans ? where best to get a diagnosis.