6.7 Diesel MPG Improving Over Time

KGDilly

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Question regarding 6.7 turbo diesel mpg.
Has anyone noticed a pronounced increase in mpg’s after about 7500 miles or so? If so, what’s up with that, just breaking in?
For the first 5-6,000 miles it was about 18mpg highway but since the first oil change and over the last couple thousand miles it is gradually improving to about 21mpg highway with no change of driving habits.
 
Mine was 21 highway almost from the get go. Saw upwards of 23 during my 1000 mile break in. Have mostly towed since so can't speak to highway mileage since. Towing mpg seems to have improved in the 1800 miles of our first trip. Getting over 12 now towing 9000 lbs.
 
Question regarding 6.7 turbo diesel mpg.
Has anyone noticed a pronounced increase in mpg’s after about 7500 miles or so? If so, what’s up with that, just breaking in?
For the first 5-6,000 miles it was about 18mpg highway but since the first oil change and over the last couple thousand miles it is gradually improving to about 21mpg highway with no change of driving habits.

I like the sounds of that! I just did my first oil change a bit early at 5k, just felt better having some fresh sludge in there. An increase in fuel mileage is always welcome!! Currently I'm running about 18 or so, but I did feel as though it was slowly creeping higher on me, thought it was just me keeping my foot out of it more. Could be that it's just breaking in and loosening up a bit. Here's hoping!!

I'll update if I notice a big difference in the next few thousand miles.
 
Question regarding 6.7 turbo diesel mpg.
Has anyone noticed a pronounced increase in mpg’s after about 7500 miles or so? If so, what’s up with that, just breaking in?
For the first 5-6,000 miles it was about 18mpg highway but since the first oil change and over the last couple thousand miles it is gradually improving to about 21mpg highway with no change of driving habits.
I predict it will keep getting slightly better over time topping out around 20-50k mile depending upon how you use it.
 
I just towed my first real load last weekend, and what I’ve noticed is that now the truck seems more responsive and shifts at better intervals during regular driving. Seems that the truck “learned” something from the experience just like the manual says it will. Definitely looking forward to any mileage increases, but not complaining at all.
 
I like the sounds of that! I just did my first oil change a bit early at 5k, just felt better having some fresh sludge in there. An increase in fuel mileage is always welcome!! Currently I'm running about 18 or so, but I did feel as though it was slowly creeping higher on me, thought it was just me keeping my foot out of it more. Could be that it's just breaking in and loosening up a bit. Here's hoping!!

I'll update if I notice a big difference in the next few thousand miles.
Awesome. Yes. I’d love to hear how it goes for you over time.
 
I predict it will keep getting slightly better over time topping out around 20-50k mile depending upon how you use it.
I just towed my first real load last weekend, and what I’ve noticed is that now the truck seems more responsive and shifts at better intervals during regular driving. Seems that the truck “learned” something from the experience just like the manual says it will. Definitely looking forward to any mileage increases, but not complaining at all.
I just purchased a 37‘ fifth wheel so we will see what it does in the coming months. My truck is still a toddler so it’s learning. LOL
 
mine seems thirsty at 7,300 on the ticker.
on the second oil change ( 1st was 1,000 miles) second at 5,000 miles). Mostly hauling trailers either a 41 5er or my enclosed motorcycle trailer so I have not ran the math. It cost about $75.00 to pull my 5er up north and back not so bad ( $2.99 per gal). ( its not that far up north).
Probably will run a road trip without a trailer next month so will see how it goes. Fingers crossed for 20+ mpg.

Anybody compare standard mode vs ECO?????
 
side note is cost me $75.00 to run my 7.3 F350 chassis up north and back with no trailer.
 
i am always been seeing 20 plus mpg but i weight 9k lbs with my tools and 300lb bumper and i still get 20 mpg i was expecting to be at 18 to 19 but i can still get 23 on the highway ... the best was 27.2 for 40 miles of flat road
 
For the OP - could you be experiencing a shift from #1 to #2 Diesel which might be causing the swift improvement in MPGs? Where I live we have summer and winter mixes.... about a month ago our Diesel pumps switched from Winter to Summer mix and I went from 15-16mpgs to 18-19Mpgs without a change in driving habits.
 
For the OP - could you be experiencing a shift from #1 to #2 Diesel which might be causing the swift improvement in MPGs? Where I live we have summer and winter mixes.... about a month ago our Diesel pumps switched from Winter to Summer mix and I went from 15-16mpgs to 18-19Mpgs without a change in driving habits.
That's what I was wondering. I think somewhere here or maybe on Facebook I made a comment similar to that. I mentioned that maybe a switch in diesel fuel was the difference. That was what I had in mind so I think you're on to something there. I also have used the Power Service Diesel supplement on and off to see what that does.
 
mine seems thirsty at 7,300 on the ticker.
on the second oil change ( 1st was 1,000 miles) second at 5,000 miles). Mostly hauling trailers either a 41 5er or my enclosed motorcycle trailer so I have not ran the math. It cost about $75.00 to pull my 5er up north and back not so bad ( $2.99 per gal). ( its not that far up north).
Probably will run a road trip without a trailer next month so will see how it goes. Fingers crossed for 20+ mpg.

Anybody compare standard mode vs ECO?????
I’ve never ran eco mode but get 21 driving easy around 65. I drove in sport mode for couple of hours and the transmission seems to hit every gear instead of skipping gears. Double tap traction control button twice quickly for sport mode.
 
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