Mpg improvement going from 17" to 16" wheels?

A Tacoma may as well be a brick compared to a low long wagon.

 

My foot is pretty heavy.. 285/75r16 3" lift and i get about 13-14mpg. Last fill up was 18 gallons, I got about 240miles to the tank.

 

24mpg, but im rolling on my 31 inch winters right now

 

I drive 42 miles each way to work every day. That consists of driving all the way trough Moab and running highway with decent hills at 65. Average is 19.5mpg. If I slow down to 60 on the highway, I get 22mpg. I drove 75 on I-70 a couple weekends ago and got 16.5mpg.

I believe it's more a matter of speed than the size of your rims.

 

This. While your tires and lift will definitely have some effect. Your speed is the biggest thing EPA estimates are done at 60mph. And in the aerodynamic brick that is a tacoma speeds above 60 your mpgs start dropping pretty quick.