6.0/6.4 Fuel Economy:
Ford vehicles equiped with the 6.4 PowerStroke diesel are not rated for fuel economy by the EPA. If economy is in question, a boost test should be performed. If boost reaches 22-25 PSI in third gear, wide open throttle under load, then the engine s operating normally and no economy related repairs need to be performed. If not in specs, then the engine will need to be diagnosed--check sensor reading, VGT and EGR operation, fuel pressure and quality, crankcase pressure, intake or exhaust restriction, exhaust or CAC leaks.
Fuel economy will be affected by many factors, including: excessive idle time (one hour equals approximately 33 miles of driving
), fuel quality and blend, ambient temperature, driving habits, vehicle use, towing, loads, add-on accessories. Broadcast Message 1271, 4450, 6989
Actually, it does seem high, by their numbers you would burn a gallon and a half of diesel in an hour (assuming you get 20mpg) of idling. I don't know i would bid it at .75 gal per hour and if you are high then you will break even with the more frequent oil changes and regen cycles.