Re: Poor fuel mileage 2004 cummins 600 3500 4x4

That sounds about right. I was told at the Cummins factory that the millage will go up a bit when I get about 50,000 miles on my Dodge. I now get 16.6 and this is with a 4.10 rear end and a 5 speed auto trans. I don't think

My new truck is getting only about 15 mpg. My dad's 1997 averages 20 mpg > or better. My truck only has about 11,000 miles on it. Is my fuel mileage > average or just too early to tell while the engine breaks in? >
Reply to
Willis Harkness
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I too have a 2004 600 4x4 dually with 6000 miles on it, automatic and

3.73?s. It has never seen 15 mpg, 14?s on the highway empty and 13?s in town. Dropped into the twelves when towing a single axle trailer with about 3000# gross on it. Real disappointing, since I traded a 99 Cummins dually that routinely got 18+. I was expecting some less but not this much. Came here to see what others were experiencing. Anyone else had experience with a dealer "adjustment" that improved economy? Has anyone seen significant improvement after the break in period? Thanks
Reply to
northzulchaggie

Snippage:

Humm, I;ve got a 2005 Dually/Auto/3.73 with 9K on it. I've always got 17.5 and about 12 towing a 12.600 pound 5th wheeler. Maybe you got something wrong. Bad injector, cloggeg fuel filter, transmission filter dirty???? Might cause some loss. I drive like it's my old Hemi. It's either or stop or balls to the walls.

Reply to
MoParMaN

I put a K&N air filter system on it and my mileage did get a little better. I even modified my route to work so I experienced more highway driving. If I baby it, I get between 16 & 17 on the freeway.

Reply to
hawkdoc

highway

Just remember that K&N?s flow more air by stopping less grit when it comes to very samll grit. There is no magic here.

Reply to
SnoMan

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