I have an 07 dually, manual 6 speed, 6.7 deisel. I get around 16 mpg around town and only 12-13 mpg's on the highway. i pull about 2300RPM's on the highway at 70 MPH. is this mileage normal or is my ring and pinion geared wrong for the highway? or any other problems?

 

I would say you're about right...at least that seems to be where I'm running. I have an '07 2500 with the 6spd manual and 6.7L. My Lie-o-meter tells me I'm consistently running high 15's low 16's...do mixed interstate and city driving, pulling no trailer as my truck is a DD. Hand calculated I've been running anywhere from hi 14's to low 16's. All depends on wind direction and speed of travel. At 70mph, I'm about 2200 rpms give or take a little...and I have the 3.73 with limited slip rearend.

Hope this helps.

Darryn

 

Not sure, but that seems backwards to me. I usually get about 16-17 in the city and 19+ on the highway?? At 70mph I'm at around 2200 rpm too, so you probably have the same gear ratio - you may want to check though. if you have the 4.10 thats why highway is worse.

 

When Consumer's Reports magazine
tested Dodge, Ford and GM diesel pickups
with the new pollution controls and the ULSD fuel
they found MPG's that surprised me with how bad they were
compared to say...a 1998 Cummins 2500 Ram 2wd

 

no offense but welcome to smog on the new 6.7

 

not sure if you guys are aware...but mopar has a factory break-in programming....around 10,000 miles the engine will go to "normal" programming...where performance and gas mileage will increase

 

That is very interesting. Do you have any more information on that "factory breakin programming"? I know the manual said to expect mileage and performance to increase over the first 10k miles but I did not know that was a programming issue. I just figured it was a mechanical break in. Where did you get that information?
Thanks

 

I have not heard anyone else say that either. Not that I don't beleive you but what do you have that backs that up or supports it? I think it would be an interesting read. Learn something new every day

 

My Dad had the service manual for an Ford Freestar...one of Fords last mini-vans. The manual said that after 20,000-25,000 (cant remember the exact number) the computer would lean out the mixture and fuel consumption would decrease. The reason my Dad looked into this is because the engine would "knock" everytime it would go up a slight incline. The van was under warranty at the time and the techs tried a couple of things and then they just finally told my Mom, "It's normal for these new engines to have a "knock" to them". I told her that was load of BS. Knocking is never good for an engine. I still don't know if the problem ever got fixed, I think she just lives with it yet.

Just another reason I ditched the Exploder I had and bought a CTD.
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We'll see if it's true or not here shortly...will go over the 10,000 mile mark tomorrow either just before I get to work or just as I leave to come home...not too bad for a truck bought at the end of August!!!