Recently took a fishing trip with my wife, sister, and brother in law. Drove down to southern Idaho to meet them in my 2017 cc lb 6.7. From there, we hooked his 2015 duramax up to his 18' boat with 75 horse engine, threw in all our luggage, and headed to lake havasu, Arizona. Roughly the same distance in both legs of the trip. Loaded to the gills with luggage, boat, and people, he averaged 16.7 mpg hand verified. My !#!* truck squeaked out 13.6 hand verified mpgs empty 😡 My old 2011 got 20 easily. I love this truck but absolutely hate the mileage. Might have to look at switching teams for as many miles as I put on. This is rediculous

 

or maybe give the truck a little time to break in perhaps?
​​​​​​​my CC LB consistently gets 17.5 to over 20 depending on conditions. But mostly high 17's.

 

I have same pickup as you, 4x4. Pulled a moderate load several times in the first 4,500 miles. 4.3 mpg, 6.1 mpg, 4.1 mpg !!!! Are you freaking kidding me ? Empty the best so far has been 10.7 all pump to pump hand calc.

 

With a 6.7? If so, take it to the shop.

 

That's odd...what kind of driving conditions? Was it all highway?

My '11 with 3.55s got 18-19 on the highway consistently from day one.

 

Yes 6.7 Diesel, 3 - 800 +/- mile runs, now yesterday the DEF gauge says under 500 miles to empty. I know it was full, did it myself. With a 7+ gal DEF tank it should have lasted around 7,000 miles (what our 2 - 2012s do).

 

My average for 800 miles so far mostly hwy running 65 mph is 14mpg 2017 f 450 with 245/70/19.5 tires i'm happy with that

 

I've only done one highway trip on my F250 6.7 diesel, so take my numbers with a grain of salt. Averaged 19.1 mpg according to trip computer over 600 miles, just me and my luggage, running between 60 and 70 mph, with occasional 75 mph.

 

Spook222.....I'm in the same boat with you. Highway...not too bad...but EVERYWHERE else...I'm getting 13 and 14. There are several threads on this...and several folks have said take it to the shop...it's not right. Does that mean ALL of us getting ****ty mileage have to take it in??? Don't think so. And you are exactly right...my 2011 also got Damn better mpg than I have so far at 6500 miles. And guys...I am NOT expecting 22...but would sure LOVE to have 16-17 like I used to...for the life of the truck like my 2011 did. And I drive the EXACT same way.

 

What gear ratio are all of you running?

I would guess these 19-20MPG numbers are SRW's with 3.31 gears?

 

Spoke222, I remember you posting a pic of your truck w/new tires. What size are they and what gears are in your truck?

 

I have close to 6500 miles on my 2017 dually 4x4 with the 3.55 axle. My lifetime average is 13.9mpg. I'd say 20% of the miles are highway towing, but lighter loads (5k or less)...the rest of the miles are a mix of city, highway, and plenty of idling in the winter. I can squeak 20mpg from this big truck if I run 55-60mph roads; I get 14-15 on the Interstate at 70mph. In town is pretty miserable.

I will also say my previous 2016 CCSB 4x4 diesel with the 3.55 axle got substantially better fuel economy. Guess its clear how the extra 65lb-ft of torque was provided to us...

 

Coming from the Duramax family for the prior last 3 trucks, the one thing I expect is less mileage (w my F350). No. 1, it's a dually and I've always owned SRW versions. But even so and on my old GM forums, past buddies seeing me leave all have commented to the likes of "It will be a great truck, hope you don't miss the mileage TS!". So this is well known among the dual ownership peeps.

Now my new F350 truck just came in yesterday, and I don't have first hand experience (yet) on the mileage. But I plan to not look much at the mileage estimator display.

Noting the new '17 Duramax is out with very close power/TQ ratings to our '17 6.7L. I have not visited either one of my GM forums in a couple of Months (just after my ordering and saying goodbye). I hope I love my new Ford so much I will never go back! TWT!

 

Congrats TS. I hope you love the 350 as much as all of us have on here!! For me...and I can't speak for others...I'm just a little let down with the mileage because I am one for forward thinking progress. Almost everything is this world has gotten better over the last 20 years....Cars, trucks, motorcycles, boats(outboard motors), snowmobiles, etc...etc...etc. But why is my diesel truck mileage going backwards???? That is just my simple concern/beef with my '17 so far. You say you won't look at the display much...but it's hard not to when it's right there staring you and your wallet in your face. Good thing now...diesel prices are lower right now....so that makes up a little difference in the monthly budget. Show some pics of that new Dually when you get a chance.

 

Lifetime average on mine is 12.1. 4000 miles on it. 20% has been towing. Approx 10000lbs. Did a trip last weekend empty, averaged 65-70 mph it did 18 mpg. Very similar to my 12 F-250. Problem is I usually drive it like I stole it so that really puts a damper on the MPG.


Sam