I have just over 10k miles on my 03 cc/da. I juiced it with the 4.61 about 5k miles ago.
When I compare my actual fuel used vrs. milage indicated by odo.It is much lower than that indicated by the on board computer.
I have been following posts and notice .5 differance ok.
mine can be off as much as 2/3 mpg. Stock tires.
Fuel filter has been changed.
Temp range was in the 40/70 degree range, and towing 17,000 combined.Good engine temps.
Trip showed about 15.7mpg. Fuel tank tells me about 13. Not loafing 70/75mph I had to keep reminding myself I had a trailer behind me.
Level 2 t/h mode.
Anybody out there had anything similar,or thoughts.All synthetics,amsol air filter.

Dam yankee in the South, but will never give in to the dam Commie attitude down here!!
My tags still say "Live Free or Die" Keep my Nh home.. Thanks ALL......