I have a 2004.5 Dodge Cummins. I expected to get better mileage, I am getting 15 on the rd and 10-12 mpg in town, anybody have any ideas on how to improve the mpg's.

 

Get a smarty for starters.

 

adjust the valve lash
clean the IAT sensor
propper tire pressure
synthetic gear lube in all boxes
tone ring mod
smarty on economy mode

biggest of all is driving habbits

 

https://www.dieselbombers.com/5-9l-c...d-2003-up.html

 

You should list any and all mods to your truck... Tire size too...

 

Oh, I'm not the only one! I get 16.5 MPG driving slow and easy. I was thinking it was because of the way it was geared low, and if it is, I would love to change the rear end when I can afford it.

 

Sort of think it also depends on the speed you're running on the highway.

At my usual "highway speed".... which, let's say I don't impede traffic..... drags me down to about 17 mpg.... BUT when in areas where they aren't so liberal with speeds, and I keep the truck under 65 mph, I can get 22-25 HAND CALCULATED.

1998.5, Cummins, Auto. 4x4. Long bed, quad cab. 3.72 (I think) gears. Banks Big Hoss Tuner. K&N Air intake.

Much depends on my the position of my "go-pedal" and how heavy my foot is.

 

I run a smarty and my mileage did not change on any of the settings.

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Maybe I should try the 90hp injectors, but is it worth it?

 

On the truck in my sig. i started before the mods with average hand calculated mileage at around 14-15 highway. after i got the goodies on right now im getting 18 on the highway which im pretty impressed with considering im a dually with 22.5's on. The smarty definatly made a difference on mine as well as the fass kit.And yes it also depends on how heavy i am on the skinny pedal

 

did you put any lift on the truck and what size tires do you have wraped around the 22.5s.