MPG Increase

My 2018 DC had 10024 miles on Saturday when I changed the oil/filter myself and put Mobil 1 0W-20 in it. Prior to changing the oil, the best gas mileage (according to the onboard app) was 16.5mpg. This past weekend I drove it 250 miles to our property in NC and returned today. My mileage going down was right at 17mpg total average for that day. Coming back today, I got 18.8mpg.

I've had the truck just a little over a year and the only difference is the oil. While it may be disputed, the oil change with synthetic oil, over whatever the dealership put in it at 5K, is the only thing that has changed. And, I've driven the truck down to NC a few times, and only once getting 16.5mpg.

For me, more reasons to change it myself and use good oil and filters.

 

I usually get 11 something - have a small lift and I can’t drive slow. Changed mine with M1 0-20 and used a TRD filter and mine went up to 12s.

 

Trusting the computer for fuel results in my experience is sketchy. I use the Fuelly app and often reset my computer when I fill it up and then compare it to the App results. From what I've found the computer is all over the map with no consistency. Sometimes it's damn near right on. Other times it's off by more than 1 mpg gallon. No clue what drives the computer.

 

In my case I was always at 11 no matter how fast or slow I drove or highway vs in town. Now I’m always at 12. Yes, it might not actually be 12 but overall it went up and stayed there.

 

Well, oil may make a difference but in all honesty, there are a multitude of reasons for a difference. For example, I recently drove from ATL to STL - got about 16.5MPG on the way up and 18.0MPG on the way back simply because of elevation changes. Hell, I get 1 better MPG when I drive from ATL to Auburn because it's downhill. Wind can play a factor as well.

The only way to test it is to control every single variable except for what you've changed.