Tank fillup sometimes shows 320 miles instead of usual 285

Does anyone know why sometimes when I fill my tank it fills up to 320 miles? For the most part it fills up to 285 miles but a couple times it has gone to 320 which is a pretty big difference. Why is this? I have a 2018 TRD OR

Thanks!!

 

@stun gun could probably help you

 

Mine bounces between 416 and 385... sometimes i average 20mpg and it shows 416, sometimes i get 21mpg and it shows 385.... all i know is I basically travel the same distance regardless.

 

Assuming you filled up with exactly the same amount of gas every time it simply means your truck got about 2 mpg better on the tanks that took you 320 miles than the tanks that went 285. But chances are you didn't fill up with exactly the same amount of gas every time, just changing the amount of fuel you put in the tank by 2 gallons could account for difference.

The info you are using is basically useless. The only numbers that mean anything are hand calculated mpg. Use the calculator on your phone. Divide the miles driven by the amount of gas you put in the truck. Then you will have some meaningful info. The newer trucks that show MPG on a display on the dash CAN be pretty accurate at times, other times they are very optimistic. My Tacoma is old enough not to have that feature and mine must be calculated by hand. My Honda however is WAAAAY off. Sometimes showing 6-7 MPG better than I get doing it by hand. My F150 is pretty darn accurate. In the 50,000 miles I've driven it the displayed MPG has never been off by more than 1/2 MPG.

Even then depending on at least a dozen factors your MPG's can vary a LOT. Road conditions, weather, heat, winter/summer fuel blends, running the AC, driving into a headwind or with a tailwind, tire inflation, towing or hauling weight, and speed are all factors. I've gotten fuel mileage as low as 12 mpg and as high as 23 mpg in my Tacoma depending on all of the above factors. For yours to vary by 2 mpg from time to time is simply not a concern.