I keep a spreadsheet with my mileages. Over the life of the truck (2 yrs old, 15,000 miles) the on dash mileage averages ~5% more than my actual calculated mileage. If I am pulling the my camper and see 11.5 mpg, I know I am getting somewhere around 11 mpg. If I am getting 21 mpg without towing, then I am actually getting 20 mpg.

Individual fill-ups can vary so that is why I do a long term mileage calculation.

 

I've been forum stalking you and you're a smart**s here too. I'll bet you're great at parties! haha

 

Cant argue with you there. lol. I like smart *** comments and have a sarcastic sense of humour.

 

I've filled up 6 times and the first 4 were really close to the dash. Last two have been off by 1 mpg or a little more. No change to driving.

 

Ditto. If I want to save on gas then I'll drive our civic. But it will not carry a ton of corn or pull our boat or carry home plywood. My last tank averaged 14.6 with 4:30 gears and paid $2.24 a gallon. I can live with that.

 

Not sure where you picked up the 80% line. The tanks are rated at a "usable" capacity. Mine is 48 and you can use all 48 on a mostly level scenario. It holds more like 50. Now your fuel light comes on about 10% left, the new ones are smart and change when they come on when you are towing.

To the actual question..... I, unlike most people I guess, understand physics and realize it takes a certain amount of power to push a 8K# truck down the road, and takes more when you add weight or wind resistance. There is only a certain amount of power in a gallon of diesel. I do drive with a light pedal when I can and use the fancy computer gauges to help me drive more efficiently but in the end it takes what it takes, I damn sure ain't gonna push the truck down the road either empty or loaded. Also, a rapid change in fuel economy can signal something wrong with the engine, not such a concern now-a-days with the trucks being automated, sensors everywhere and the program giving you an indicator if something is deemed incorrect.

I keep an eye on my fuel consumption mainly to know what MPG i'll get under a certain load so I can calculate costs. I have never calculated by hand with this truck, the computer is close enough. If you have one of these trucks, and diesel prices being the highest choice now, and if someone is concerned about pinching pennys then they may need to reevaluate previous choices.

 

I've hand-calculated and found that my true MPG was 4% lower than the meter read. I adjusted this using the engineering screen, set to a bias of 960 (96%). Now it's within about a percent every time. What is interesting is that people think hand-calculating is somehow more accurate. It needs to be taken as an average over time (to account for exactly how full you get the neck of the tank full) and after you accurately calibrate your speedometer. If your speedometer is off 3-5% (as many are), your MPG hand calculation will also be off 3-5%. I assume the odometer is accurate once the speedometer is calibrated but that's also a possibility for error.

 

One of my dirt bike riding buddies, well known for his exaggerations of the truth, just leased a 2019 Ram 1500 with the 5.7 and10 speed. He was claiming that he saw mpg in the 30s while on a 4-lane recently. I've let one of my other buddies in on my plan to tweak the entry on the engineering menu in my truck, prior to our next trip in it. Mine will be showing 35+ on the dash, while pulling an enclosed bike trailer...

 

That's a good one. Let us know if you can tweak it that much.

Might help in the resale value, if the buyer is clueless.

 

I have never had someone ask me about fuel mileage at the gas station in my entire life.

 

We had a guy like that in Alaska. He swore his 4x4 Duramax got 25+ mpg pulling a 4 place snowmobile trailer with 4 big guys inside the truck. Finally it was his turn to drive and we had a 200 mile ride to get to our spot and 200 back. That meant he used 16 gallons of diesel which at the time cost $4 a gallon. At the end of the trip I gave him $16 for fuel saying that was my share. He never claimed 25+ mpg again