:eek: -:t I BOUGHT A NEW 05 DODGE 3500 4X4 DIESEL 4 SPEED AUTO QUAD CAB 373 REAR GEARS. I GOT 12.8 MPG EMPTY AND I TOWED MY 5TH WHEEL THIS WEEKEND(13000 LBS) AND GOT 9.1MPG. THEESE WERE FIGURED BY HAND. THIS IS UNEXCEPTABLE. ANYONE HAVE ANY IDEAS OTHER THAN TRADING IT FOR A DMAX.:help:

How many miles do you have on your truck? You know the more miles you put on these Cummins the looser they get, and fuel mileage will increase. My Bro has an 04.5, 600, 4x4 Quad cab, with 4.10 and when he first got it he was seeing 9-11 miles per gallon. He has about 18k on it now and he is up to 15. I here on these new Cummins that @ 30k the ECM does something and the fuel mileage really jumps up. I have a 2nd gen and you can see my sig on the mileage I get.:beerchug:

dont even expect good mileage until she gets broke in 30K+ ;)

What they said..... it takes 20-30K miles to loosen up the beast. I have an 05 3500 DWR 2wd (5k miles) and am getting 16 city / 20 hwy. Towing a 30ft / 11K lb trailer it is 11.

man i was expecting 15mpg right out of the gate. 11mpg towing. my brother inlaw has a new power stroke he has been at 15mpg from the first tank. are the dmax's get any better mpg?

It is all in the design and my knowledge of engine design is limited, but the PS reaches max torque of 570 at 2000RPM where the cummins hits its max torque of 610 at 1600RPM. To get there you need fuel, so my assumption ( and please correct me guys) the CTD will use more fuel since most of its "normal" operation will be near peak torque.

Another thing that you need to remember is that a Cummins is a medium duty engine, its alot tighter and it needs to loosen up. Powerstrokes and Duramaxs are light duty V-8s. Apples and Oranges.

Have your dealer make sure your computer has been updated (per chrysler bulletin) for "poor fuel mileage". This will add about 1.5mpg immediately. Once that is done it will gradually get better as you get miles put on it.

Mine started out at 12.8 mpg empty. Now with 20,000 miles I am getting 21.6 highway and 18.7 average highway and intown. I get around 11.8 towing around 8500 lbs varying speeds from 25 to 75 mph.

The more I tow and drive the better the fuel mileage is. I also thought it was very doggy on power when new. Now it accelerates better and feels more powerful as well.

Hang in there, its disappointing at first especially at 2.50/gallon. Once you get it broke in you will love it.

Thanks Guys I Will Try To Keep My Head Up High. I Was Told Tonight That A Bud's Friend Just Bought A New Chevy And Is Getting 18.9 First Tank. Man That Hard To Take! Well I Will Keep You Posted

Powerstrokes and Duramaxs are light duty V-8s.

the navistar vt365 came out in medium duty service before ford rebadged it 6.0psd and stuck it in their trucks... it was designed for medium duty service, but built like a light duty engine imho

Give it a little time. I still see mine increasing ever so slowly. At first I got anywhere from 14.5 on tank to 18. Now I stay right around 18 no matter what (23,000 miles) I have heard that it continues to get better as you put miles on it. So far I would agree. It's still unfair that diesel is $2.29/gal and gas is $2.13. But then last summer I paid $1.69 and gas was $1.99 to $2.13.

Go back to the dealer for the reprogram. I have an 05 4x4 crewcab auto with 373's and it gets atleast 14 to 15 in town.. On the highway I've seen 19.. Mileage drops dramatically if go over 68.. Don't ask me why.. 64 to 65 is the sweet spot.. Right at 1800 rpm... Dealer reprogram, and good luck...

Mine now has around 1,000 miles...