I tow a 26' TT that weights @ 7500 lbs loaded. On my first trip with a '00, 2500, 3. 55, auto I got 8-10 mpg traveling from LA to VA. The power also seemed sluggish at times. I'm new to Diesels and traded a very good '97, 318, auto, 3. 55 that got that same mileage with the same trailer. It took 2 yrs for me to convince my wife to let me get a DSL for the power and mileage. Was I suprised, and not pleasantly considering the trade I made and the new $28K note. I listened to all the campground tales of 14-16 mpg and towing 12k lb 5th wheels with power to spare. Be honest. Is my performance typical or could I have something I need to check? HELP!!!