Do these newer 6.7 get better milage with break-in?

[Highcountry]

Do these newer 6.7 get better milage with break-in? I'm curious more than anything. I thought I'd heard no, but lately mine seems better. I'll start by saying I know the gauge that states MPG is overly optimistic. I've had my '20 since January of '21 and it usually shows 18.5, which seems to be more like 17. In the past when driving on the freeway unloaded and keeping speed down, I could end up showing 22-22.5 if I had a really light foot. I now have about 22,000 miles on it and it seems to be doing better. Almost identical trips I experienced the 22-22.5, I'm now showing up to 24 and change. I expect that's also quite optimistic, but has me wondering if it's breaking in and improving? Could the replaced injector pump be a factor? Stock tires 58 pounds of pressure, 66 mph and under, very little cruise control use

 

[Will_T]

Mine has never changed. But most of my driving is towing the RV so I don't even think about the mileage. Plus I have a 52 gallon tank.

 

[Brutal_HO]

While there's really no "break-in" for the Cummins, cylinder "finishing" will improve over time and has an affect on performance and mileage. If you tow heavy, that' generally around 10-12K, much longer if not towing.

I can't think of any case where anyone has seen or documented any change based on the HPFP recall/change. My unloaded mileage has always sucked, but my driving habits and use of my HO are not very conducive to good MPG.

 

[oledirteh]

ive had 4 6.7's and to me personally, from what i have noticed, at about 7500 miles i have noticed a slight increase. my 21 was getting 20-21 mpg highway most days on the lieometer.

my 24 HO 6.7 hovers between 18.5 to 19.5 mpg highway. didnt see any change after the 7500 mile mark.

 

[Deleted member 47449]

Our 2024 Ram 3500 4x4 6.7L and 3.73-1 axle gear ratio with 7,500 miles on it gets around 18.4 MPG on OEM sized Toyo C/T's. I changed out the OEM Transforce HT tires immediately after purchase. They weighed 49 lbs each. The 275 70R18 Toyo tires weigh 77 lbs each and have a more aggressive winter rated tread. That doesn't help with MPG's. Still would prefer 4.10-1 axle gear ratio on the new truck as is on our 2016 Ram 2500 4x4 due to our rural steep mountain grades. It's a 16% grade in Northwest Colorado which isn't good for MPG going up.

 

[HarryN]

I don't know about diesels, but for my gas powered vehicles, they definitely get better mpg in cruise control than using the gas pedal.

 

[56ram2500]

Our 2024 Ram 3500 4x4 6.7L and 3.73-1 axle gear ratio with 7,500 miles on it gets around 18.4 MPG on OEM sized Toyo C/T's. I changed out the OEM Transforce HT tires immediately after purchase. They weighed 49 lbs each. The 275 70R18 Toyo tires weigh 77 lbs each and have a more aggressive winter rated tread. That doesn't help with MPG's. Still would prefer 4.10-1 axle gear ratio on the new truck as is on our 2016 Ram 2500 4x4 due to our rural steep mountain grades. It's a 16% grade in Northwest Colorado which isn't good for MPG going up.
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And here I thought the few 10% down grades in north Idaho I drove years ago were bad, your 16% takes top honors