6.7L Cummins Forum

I purchase my truck back in January 2008 and have loved ever since. Within the last three months or so and have seen a huge decrease in fuel mileage. Originally I was getting 16 around town and 22 hwy and now don’t seem to budge much above 13. Currently there is just over 58,000 on it. This is the first issue I have had outside of some emission trouble when it hit the 20,000 mark (consistent check engine light, soot in the turbo, and clogged DPF, etc). All were covered under warrantee and they cleaned turbo, and replaced DPF. There have not been any other issues with check engine light or other on-board warnings since. Took it to the dealer last week and they contributed the decrease in fuel mileage to the excess fuel dumped into the exhaust stroke to be burned in the DPF. Has anyone else experience an issue like this? Any known fixes or modifications that will help?

Thanks,
Mike

If you weren't regenerating at first then you would see outstanding MPG as you were but you also clog the DPF as you did. I drive all highway and the best I can get unloaded is 17MPG which I would think in town would be around 13 or 14 MPG. The only thing you can do to increase MPG is gut the emissions. Interestingly, 17 MPG is the best I could get in my 1/2 ton Nissan Titan so I'm happy.

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

I have been getting around 15 to 16 intown on my daily commute, but lately all I seem to get is 13 to 14 same as Mike. The towing mileage has been down as well. Last weekends haul is a trip we make about every other month and we were down 2 MPG, normally on the 300 mile round trip we would get 12 to 13, last weekend we got 10.
But on the lighter side the V10 Gasser we would have had to put fuel in it to even think about coming home, this one does it easily on 1 tank full. Dang I love this truck.

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07.5 3500 Quad, SRW, 4X4, Laramie, Leathered, Dark Metallic Gray, 6.7, 68RFE, 20K Reese, Ride Rite's, 2 Viair air compressors, Bully steps, Kleinn Locomotive air horns (5 in all), Billet polished locking fuel door, 'A' pillar mount Auto Meter Pryo, PML X-deep trans pan
06 Durango 285 RL 5'er Lifted by KZ

I agree 13 is the norm! Clogged turbo, new DPF, and catalytic converters= new program and less mileage. 07.5 3500

It seems curious that a number of people in different areas have seen a drop in mileage. I wonder if it has something to do with the quality of fuel available right now. I have a 2007 with the 6.7 and routinely get 17 to 18 around town and 20 plus out on the road. I have noticed my mileage drop while pulling my 5th wheel and thought I neede to change the fuel filter. By the way Dodge has re-designed the fuel filter so that the inner element can be replaced seperately, but the price of the unit has gone up.

Mark

The best I seem to get is 18mpg on the highway and 15mpg around town, pulling 14000 trailer and it drops to 11mpg. every where I go is up hill to get out of the valley!

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Winger
2008 2500 Silver 4x4 6 Speed Auto Big Horn Edition Volant CAI Magnaflow Muff Edge w/ Attitude
1990 Honda GL 1500 Wineberry 125,000 Miles
2005 Honda GL 1800 Candy Blackcherry 50,000 Miles