I was really pleased to see what high average mpg I was getting on the display in my brand new OBW (2006 2.5i, manual trans). 28.5 mpg and up on my regular commute of about 22 miles highway and 3 subarban/city.
Then I filled the tank. The display, which I had reset when I first filled the tank, said 26.1. The number of miles divided by the output of the gas pump came to 24.35.
This is a 6.7% difference. In the wrong direction.
It's only one data point, and I will of course, check after each fill up for a while, but it leaves me wondering what other people are getting when they compare the mpg display to real consumption, and what people here, and Subaru, think are reasonable tolerances.
Charlie in de Bronx