TowRig.com - Diesel Discussion and Tow Tech

I have an '02 GMC 2500HD with the 6.6 D'max engine. I have calculated, at best, 14 mpg and approx 10 mpg towing the 5th wheel. What could be wrong?!? :confused:

I get 9.5 towing my 30ftTT but i also get 23.5 with a predator on 85 @ 65MPH

First off you don't buy this type of truck and expect to get good mpg.
I pull a 38ft. fifth wheel that weighs about 19,000 lbs.and only get about 8mpg. you might look in to some up grades ( air intake,exhaust, and chips to increase power):)

Yup, mpg has alot to do with driving style, if ya understand the concept, diesel tow rigs are just big tractors, not hot rods. Get em reved up and lock on the cruise and there is where your best mpg s are going to be. And reiterate what they say, get a tuner, open up the airbox and exaust . Get yer foot out of it save forwhen ya need it. , try not to hit or climb any curbs, some of the 02z were sloppy? might be time to go thru yer block and tranny for some new snap. So says Alasksa Dave, who is now in Phoenix, seeing some fine lifted snappers cruisin round this winter, especially the GMC, Durimax zez.Fuel just jumped to 3.50 gal.:stir:

First off you don't buy this type of truck and expect to get good mpg.
I pull a 38ft. fifth wheel that weighs about 19,000 lbs.and only get about 8mpg. you might look in to some up grades ( air intake,exhaust, and chips to increase power):)

I would say that you would get a diesel to get good mileage (at least in comparison to a gasser)...