I have a 2000 CC 4x4 LWB SRW. When I ran the Edge when it was almost new, 18 mpg empty was an everyday occurance up until I went to a TS chip and mileage empty dropped to at best 15 mpg. Sold the TS and tuned with a DP, same as the TS. Now, before I get slammed, the DP tuning is bad ass and very fun to drive and I feel there is considerable difference tuning. Just made a 500 mile trip last week and total hand calc tally was 14.9 empty at 75 mph. Pooned tank so I know it was just as full as the first tank. I run around 12-12.5 pulling heavy on any one of our trailers, depending on fuel on fuel and elements of course. This is based on summer fuel, winter is, well you guessed it, worse. /ubbthreads/images/graemlins/shocked.gif
Get this, my 2003 6.0 (same set up and gearing) norm was right at 18 mpg empty and 14-14.5 loaded until they did the last reflash. Now it is where the 2000 7.3 is at. It is programmed with SCT.