@
korborh
I've been tracking the displayed MPG for my own amusement. Here are my last 14 fill-ups (each after about 350 miles). After the first seven fill-ups, I reset the displayed MPG so that the mileage would be computed only on the current full tank of gas. Starting with the 8th fill-up, I did not reset the 4Runner-calculated mileage, but let it accrue. I also kept records of miles driven and gas used, so I have my own calculated MPG estimates after each tankful.
As you can see, my calculated MPG and the 4Runner-displayed MPG are quite close for the first seven fill-ups. After that, my mileage varied based on my rather erratic use, but the 4Runner displayed mileage was only mildly affected by the mileage I got after each tankful.