Long time listener, first time caller! Ok so heres how I ended up with a 6.2. After being a bow tie guy for years I bought a 99 SD because at the time the GM diesel was junk. Then moved to an 04. With 6.0. Kept it till this year because all the newer diesels scare me with all the emissions crap and everything. Decided it was time for a new truck again and figured give the 6.2 a shot. Had dealer search and find me a crewcab 8 ft box 4x4 with 430's. I like the truck but the mileage is atrocious! I did lots of reading on hear before buying and I can tell you I am getting nowhere near the mileage I see guys claim. Pulling 32' camper on secondary roads for 200 mile round trip I get 7.7 mpg. Unloaded and unhooked I have yet to break 10 mpg! I have kept my foot out of it and have basically babied it for the most part. I got it mid sept and its only at 964 miles thus far so I am hoping that as I get more miles on it that it will improve but that will be awhile as I drive a car to work and it is basically parked till march-April when the snow melts and the salt is off the roads. Anybody else get horrible mileage from the get go? If so when did it get better? Any input is appreciated. Thanks in advance!

 

Welcome aboard...

You may see a slight improvement around 5k miles, or at least I did. Your mileage is a little low for taking it easy. I get around 12-13mpg around town and 14-15mpg on the highway if I keep it 65mph or below. Towing 16k I get 7-9mpg around town, 9-10 on flat highway.

Unfortunately, this is the nature of the beast you purchased. The diesels do get better mpg but you pay for that upfront and in service.

I have a 5 Stars tune on my truck which hurt my mpg because it is much more fun to mash the go peddle than before.

 

Is the truck stock(tires or lift)?

 

What MY did you get? I got mine the middle of November and have just under 1100 miles on it (it's my daily driver). Pretty much all of it is around town and unloaded, and I'm averaging right at 12mpg. I traded from a Fusion Hybrid, so I learned how to get really good mileage on my daily drive (Fusion at around 27k miles with lifetime of 44mpg). That said, I have really stomped on the pedal a few times with the SD, just a get a feel for what it could do of course. LOL

 

My front hubs were locked when I picked up my truck and I was getting around 10mpg around town. The mileage went up 2mpg after unlocking them and a bit higher with much improved performance after 5000 miles. BTW, towing large is not recommended before 1000 mile break in period for the rear end.

 

900 miles.. it still brand new... still have machining on the brakes.. seals are still tight... everything is still getting polished..

and the truck is an aerodynamic BRICK.. and going over 60mph kills gas mileage.

I have 150,000 miles and 2 wheel drive, with my 6.2L and get 12 around town.. 16 on highway.
towing I get 8 to 9.
.

 

Enjoy the truck and don't worry about the mileage for another 5k. Gasser and 4:30 gears, there are guys out there that would to take it off your hands and not worry about the mileage.

 

I did not see one ounce of improvement in mileage at 5k miles...lots of people say they have...not me. the 430's surely hurt you some but basically you're driving around a big Ole heady duty truck and it sorta is what it is. I have a 2016 lariat ccsb 4x4 6.2 with 3.73's. I tow under 5k 35% of the time...I don't get on it too much and coast to all red lights and stop signs and I get about 12.5.

 

Don't feel so bad my dads 15' 6.2l CC doesn't get the mpg most people here post either. Its on par with or a little worse than my dads old 03' 6.8l CC configured the same as the new 15'. With these larger gas engines what I have noticed is that idling and short trips can really suck up the gas. Cold weather, ethanol in the gas and winter gas blends sure don't help mpg either.

 

First let it break in before you get to worried. When we pull on secondary or two lane roads our mileage is down around the 8 range but a lot better on the interstate.

Denny

 

It's your gears, definitely your gears. Bring it down here to TN and I will put in some 3:73's that are just broke in with 12k. And I'll even take those terrible 4:30's off your hands, all free of charge.

 

I'm glad I'm not the only one getting that kind of mileage. These trucks aren't great on mileage. You say you keep your foot out of it. I've tried as of late to really concentrate on diving with an egg under my pedal and for one tankful I averaged 12 mpg mostly highway and no pulling. You really have to baby it to get better mileage.

 

Colder temperatures will give you worse mpg's. I'll get 1 to 2 mpg less in real cold weather. I was averaging 14.5 mpg but the weather has gotten colder and I'm getting 13.3 right now mostly city.

 

Both the 2011 and the 2013 6.2's I've had felt "tight" and got lousy mileage the first 5,000 miles or so. Both had 3.73 and both averaged around 10-11 combined city/hwy.

I've gotten close to 16 in the 13, all highway and all 65 or under with the cruise. Usual is high 13's, low 14's. Around town sucks it up, no doubt..it takes a lot to get nearly 8,000# moving. What surprised me was how much even a small, low, open MC trailer hits the mileage.

 

I'm another one of those "drive it like there's a raw egg on the gas pedal" types. It makes a *huge* difference on how you drive the 6.2 . With winter finally showing up here, I'm in 4x4 most of the time, and letting my truck idle more to warm up and defrost the windows (I park outside), and my mpg average is still hovering just above 13 (but falling). Most of this has been city driving lately, but next week I drive across the state for some out of town work (if the incoming storm doesn't shut down all the roads again).

My last 3K mile round trip unloaded to Phoenix, AZ and back was over the summer. All highway (obviously), mix of flat land, rolling hills and mountain grades. I averaged between 70 and 80 mph, the only time I was under 70 was in towns or if I hit construction zones, and my mpg for the entire trip was 14.9. I was fortunate to not get into any serious head winds which helped. I bought only standard grade gas (85 or 87 whichever was avail at the pump). My truck is bone-stock.

Last "big" trip pulling our 5er was 900 miles, 700 of that towing, 200 of that was unloaded site seeing, to Mt. Rushmore/Blackhills area and back, averaged 9.5 mpg. Pulled through flat ground, rolling hills, and steep mountain grades. Pulling our 5er, 11,800 lbs scaled weight, 34' long, 13' high. Kept up with traffic at all times, pulled between 65-70 mph on open highway.

The biggest hits I've taken to mpg has been from wind resistance. When driving/pulling into a headwind, my mpg drops dramatically. Worst I've ever seen was 5.5 mpg, and that was pulling our 13' high 5er into a heavy head wind, 30 mph head winds with gusts to 50 mph, taken straight head on into the nose.