I am am someone with an axe to grind with these trucks so I am coming in with a bad attitude. A 6.7 w/ a problem is the rule, not the exception. A truck that cannot be driven short distances, cannot idle for long periods of time, and has to be constantly driven hard on interstates for long periods of time sounds like a vehicle with issues.
My dealer told me the same thing "Gotta get er on the highway and run er". The highway is not local nor on my work route so why should I spend the extra fuel in doing so??? I run an 05 5.9 preforming the same tasks and get better results (mpg is almost 2X 6.7). I can "blow er out" on a back road without the highway and without the breakdowns, lost hours and money.
Call me a pessimist but I'm gonna say that should I run the vehicle hard and it breaks down their gonna blame it on me.
There is nothing mentioned about driving style in the ads or commercials???
I do however, remember spending almost 50K on the 6.7 just to be told that every time it broke down, it was my fault???
And guess what??? For 1K more I can get a dpf delete kit and totally void my warranty.
NO THANKS. KEEP THAT JUNK.
I suggest you check all the sites regarding this vehicle and you will find nothing but trouble. From buses to emergency vehicles everyone that has had a taste of the 6.7 has spit it back out. There are people out there who are trying to gather names for class action suits.
A 6.7 with problems is not the exception, IT'S THE RULE!!!
Just my .02