My Tacoma has been lying to me!

Bought my Tacoma a few weeks back and posted here about the impressive 28.6mpg the dash showed after my first tank of gas. The comments made me very curious about the accuracy and I decided to track the mileage the old fashioned way.

I tracked 6 fill ups over a 2 week period under various driving conditions which included: my typical work commute (mostly highway), a 1,400 mile road trip and about 100 miles of city traffic (more like suburban hell traffic) loaded with boxes and furniture helping my daughter move.

The results:

Total 2084 miles traveled, 92.99 gallons used at 22.4mpg while showing an average 27.56mpg per tank on the truck!

Best 354 miles traveled, 14.68 gallons used at 24.12mpg while showing an average 29.9mpg per tank on the truck.

Worst 339 miles traveled, 16.32 gallons used at 20.77mpg while showing an average 25.8mpg per tank on the truck.

Although not as impressive as the truck was indicating still better than my previous Silverado at 19.4mpg average, which I now suspect was also a lie. Without having the Silverado to validate its mileage I my best guess is the Tacoma is still about a 25% improvement in mileage. On the same fill up cycle of approximately every three commute days I was putting about 21 gallons in the Silverado and now put about 15.5 gallons in the Tacoma.

Curious if anyone has any insight into why the per tank mpg is so far off? Tires are correct original size and I validated the odometer with gps. 🤔