the key is to keep your foot out of it. every time you hotrod it or blow smoke, all you're doing is dumping diesel out your tailpipe. Boost is also your enemy when it comes to mpg. I'd bet you could get 5mpg better cruising at 60-65 vs. 70-75.
stock my truck got about 14 city and 18 straight highway. i'll update with some #s on my dp once i run a few tanks through it.
2002 Arizona Beige F250 Ext Cab Short Bed. 7.3L 6spd 4x4 140k
2" leveling kit, 285/75 Mastercraft AT2's,Napa BFF, DiPricol Pryo/Boost, DP F5 NS/stock/hi/40/80/120/140agg-lope, Toolbox, Audio goodies, IH shiftknob
muffler delete, CCV reroute, AIH/Foil delete,