New guy here; considering buying an '07 6.7 dually crew cab with 6 speed manual but have been told how bad the fuel mileage of the 6.7 is. First; is there any truth to this and if so, what can be done to help get the mileage up without spending another ton of money?   Thanks for any help,  

hey another new guy:: own a 6.7  2500 dodge  4x4 quad cab all factory setup.  i been reading the threads,   looking for answers as all this jargon is new to me.  right now running down the road empty  i am getting 21 mpg  with 2500 miles on the counter.  

I have a 2008 Quad cab 4x4 2500 "big horn" edition with the 6.7 bluetech diesel and about 22,000 on the odometer but my overhead has NEVER been over 15.1 MPG! even at 55-65 mph road trips.There is so many heavy emissions controls on it the poor thing can't breath.I'm going to do the DPF delete first chance I get it will be worth the money saved in fuel alone.