A little help out there? Bought a Chev '02 crew cab Dually 4wd a year ago and it now has 35K on it. It seems to me that it is rather under-powered and the mileage is not where I've heard it should be. With a 4000 lb camper and pulling a 4000 lb boat I have to be pedal to the floor to keep it at 65 mph going up a fairly moderate grade. Also the mileage in that configuration is about 11 mpg. Furthermore, when pulling/hauling nothing with mostly hwy driving I'm getting only about 15 mpg. I brought it to Chevy and they said everything checks OK. In the winter with #1 that 15 drops to 11. Not good!? Any ideas out there? Thanks.

Cant tell if your in the USA or CDN. so I'll give both just filled up, running around town 903.4 miles or 1494Km , fill up 214Liters or46.5Cdn gallons or 56.3 USA gallons so that = to 20miles/gal Cdn or 16.8 USA /gal. Hyway driving I usually get 24 miles/gal Cdn


Towing 10,000# I have never gotten less than 11miles/gal USA in Florida on the flat lands I have gotten 14 miles/gal USA at 55 mph.


A lot of states have a speed limit of 55mph for trucks towing trailers I found I always had good fuel economy there.


good luck

AK, I have the same configuration as you(see sig.) As to the power issue on moderate grades topping out the hill my foot is in it and 65-70 is my speed also. I'm only getting 12.7 with the camper and 10.7 with the boat and camper. I drive as fast as the big rigs since they should know what they can get away with. So 65-75mph is the norm for me in Ca. towing. I feel your pain. Compared to the 454's I've owned this milage is great. As Letsgo mentioned there are ways to economize but as Sammy Hagar says "I can't Drive 55"http://www.dieselplace.com/forum/smileys/Cool.gif

Thanks for responding guys, I really appreciate it! Sounds like the 55 mph vs 70 mph may be the issue. I'm always shooting for 65-70. letsgo, I am driving in Alaska so US gal. Also, as per the advice of a mechanic friend I drove a couple hours with a load with the air filter removed and it seemed to perform better. ( no stats though.) Have you guys tried one of those K&N air filter setups. I've heard good things about them for gas trucks.
Thanks again!

There is a long thread about air filters that says the OEM filter is the best. Probably waste your money changing it out.


When did you last change your fuel filter? I find there to be quite a difference when I put in a new fuel filter.


The speed does make a difference. I pull around 14K and if I keep it above 65, usually close to 70, it will maintain that at the top of the hill. If I let it drop down into 55 or so, That is my max. However, I'm not sure I would want to have your slide in setup going more than about 55 ;)

Rockin, Thanks for the info. I'll drop in a new fuel filter and see what happens. I'm at a loss right now figuring this thing out. :)

This doesn't sound too bad. You have to keep your speed down with a diesel. THey don't like to rev. The Duramax makes great power but diesel burns most efficiently slowly. I am getting slightly better than you but I don't have a dually. Without pulling the boat with my slide-in I have got 9.5 US mpg at 75mph in Montana at almost 100 degrees and a best of 17 US mpg at 55mph with a tailwind in cooler temps. Empty I can get a tank average of 21 US mpg if I keep her slow on the highway and reduce my idling time. THe Duramax seems to use more fuel idling than my 6.5TD.