If you own a Cummins, it is a right of passage to encounter such buffoonery. I just smile and walk away. I may even roll my eyes as I turn around to walk the other way. lol

 

I've seen my lie-o-meter show over 40 but that was just after zeroing it, running down hill coasting......normal hwy is about 20, off road is about 12-14

 

Stock truck I get 13-14 combination back roads/highway driving. Today towing our 14k fiver in 25-30 mph winds in Kansas was getting 8 mpg running in fifth gear at 60 mph. If not towing in wind, usually between 9 and 11 mpg depending on the terrain.

Bob

 

That's pretty much where I am, too.

 

Me three. Only had my truck since June 1st, but so far that's about what i'm gettin. I might be about 1mpg higher empty at about 14-15.

 

I work with a guy who insists his 03 duramax is getting 27 on the highway-bone stock.

Before ULSD I was pulling 18-20 on my Montana runs, now I see about 15-17.

Altitude makes a big difference, a run from MT to CO across WY netted me an honest 20 a few summers ago, flat and a bit of a tailwind and running about 65 steady, and that was hand calced....

 

Several years back we traveled with our13k fifthwheel from Central Oregon, to Missouri, Virginia, and many other stops and then back home. We got about the same as you and also about the same as you without the trailer.
Yep we ran into some people who claim they got unheard of mpg but mostly the people were pretty honest. Maybe the ones who got good mileage went by the lie-o-meter on the over head!lol

 

A commonly shared experience too.....

I'm not sure why more people dont question the legitimacy of stringent emissions laws given the fact that most vehicles prove see a reduction in fuel mileage with all the new gimmicks introduced thats intent on reducing fuel emissions. Maybe I'm just crazy but if you're using more fuel to travel the same distance then how are you supposedly creating less emissions..... Where's all that extra fuel going?

 

There you go, thinking again.

 

Sorry..... I shall retreat back to my hole in the ground.

 

I was filling up my previous duramax truck a few years ago and another duramax pulled in. I asked what he got for mileage and he insisted he sees over 30 mpg. I called him out on it right there, explaining that's awful odd since I have the same truck and get 13-14 no matter what. All hand calculated over years. I think he explained the discrepancy away with maintenance. I'll have to try and find some of the magic snake-oil he puts in his drive-train. But he was sure of his ridiculous numbers. I shook my head and walked away. On another note, I think a big problem with comparing truck MPG is the vast array of configurations. Different ride heights, different gears, different tires (both size and tread pattern), running a cap or tonneau, srw or drw, 2WD or 4WD, added weight of tools and boxes etc. And use too. Obviously towing uses more fuel than dropping kids off at soccer practice or getting groceries. It all factors in a lot. That said, my current 01 24V gets about 13-14 avg, 15.6 once. But I live in real "town". Dense urban traffic, stop and go. Not a one stop light town. That isn't real city driving. Also some guys tow and that drops your avg even if you had the trailer on only a small percentage of a tank of fuel.

 

I hear ya. but I think a vehicle can be cleaner burning and burn more. It's just going to heat in the exhaust. Hence the lack of efficiency. Burning fuel in the exhaust make a lot less power than burning it in a cylinder. haha. That said, the ag industry's contribution to air pollution is much larger than the entire transportation industry of which our diesel trucks make up an even smaller percentage. So it seems to me like someone had invented some clever emissions components and then lobbied politicians to have their use made mandatory. But I'd have to do some research to back that theory up. But it wouldn't surprise me. The other interesting, though I'm sure unintended, side effect of all this emissions crap is that it's put the price of new trucks so high, guys are just running the older, less clean trucks longer now anyways instead of upgrading. So a lot of good that did. LOL. Just my $.02.

 

In that way CARS, (Cash for Clunkers) was effective. While it did nothing but skew numbers for Detroit, it totally screwed up the market you and I buy trucks (and parts) in. Witness the inability to source key components, some of them safety related like axle nut retainers.

Government isn't the solution, it's the problem.

 

My 01 developed a weird clunk that was affected by braking and a squealing. Came to find the dumba$$ that did the brakes didn't put back in one of the bolts that holds the whole caliper to the spindle mount (names I'm sure are wrong) so the whole caliper could move a bit and was rubbing on the wheel. I couldn't believe how hard it was to track down that stupid little bolt in a hurry. Only the dealer had it special order. I had to go to a specialty industrial supply for a similar bolt but not identical bolt.

 

Any engine running at the same level of internal efficiency as all other similar counterpart engines can NOT use more fuel more "efficiently" than the rest of those comparable engines. Its just not physically possibly. Also, the only way an engine can be more efficient is from the inside out, not the outside in. Meaning, adding things like particulate filters to diesel engines isnt fixing anything but merely masking what environmentalists feel is the issue.

If none of what I said was accurate then all diesel smog testing wouldn't be a "visual" test but rather metered tests like gasoline engines. Sorry society but we're being played as pawns in this diesel smog scam.

By the way, the agricultural industry isnt the problem either otherwise there would be mandatory emission regulations on those vehicles as well. But just for giggles try researching what level of pollutants are global and how much of those pollutants are created by "American vehicular transportation". You'll be shocked to find out that even though the main stream media, environmentalism, and the government continually mind warp us into believing we're the problem, we're far.....FAR.....from it.