You push a brick through the wind at 78 MPH and think 15 MPG is bad?

 

I have a 2018 2.7 supercab 2wd with 3.15 gears and I have not been able quite get to 25. Closest I was able to get was 23.8 (according to the truck, I don't hand calculate). That being said, any long drive you make leaving Houston you will hit 75mph zones, and driving 72 in a 75 is not something I will do, so I cannot directly compare.

I had a 2014 Tremor (RCSB 3.5 Eco 4.10 gears) several years back. Best I got on extended highway drives was 18 mpg at 78-80mph on a 300ish mile drive. Around town I was lucky to get 14.

While I would expect better than 15 mpg, you were driving a 4x4 crew cab truck almost 80 mph. I don't know the speed limit, but I know the difference in fuel consumption between 70mph and 80mph can be quite drastic. I believe it also has 3.73 gears, which wont help anything at 80mph.

 

I drive a 2017 Platinum Super Crew 4*4; It's a 3.5L Ecoboost, with the max tow package. I bought it in Kansas City and drove it home new, off the dealer lot, to Dallas; roughly 500 miles. The truck showed 22mpg. I'm still driving it; I just hit 100,000 miles. It's still good for 20-22 on the highway, up to 80 with cruise control on. Cross 80 and the mileage drops. And you can't drive it with the cruise off and get those numbers. Around town here there's still a lot of highway driving, but it regularly gets 16-17 on a tank in town. Now, through in a strong head wind and the mileage will drop, but not so much on anything other than a direct headwind.

Just another data point.

Greg

 

probably empty too...lol I'm amused the OP had a "diesel" platform in a 1/2 ton truck.
I swear this "1/2 ton truck mpg" thing has exacerbated uncontrolled over the past 15 years. Have these folks never heard of mid sized???
Ive owned a few diesel 1 tons and a bunch of gasser 1/2 tons... 15mpg is pretty much the defacto
standard mpg across all platforms in my experience. Typically the msrp equals about 250,000 miles worth of fuel
cost to operate.

 

This.

I have noticed my mpg drops from 19-20 to 17-18 when cruising speed goes from 65 to 75 mph.

 

Comparing a small diesel engine to a gas engine for fuel mileage isn't really a fair comparison. Just like saying the 3.5 Ecoboost accelerates much faster than the diesel isn't a great comparison. If anything, I would like to know how the 2.7 V6 Ecoboost compares to GM's 2.7 turbo inline 4.