The gauge you speak of works in a dynamic fashion. First of all, it only works once average MPG is established. If you reset the trip computer, then it will take 1-2 miles before an average appears.
The gauge then operates with the center point (halfway between + and -) representing the average MPG. I.e. closer to the "+" means you're currently doing better than average, and vice versa.
The gauge then operates with the center point (halfway between + and -) representing the average MPG. I.e. closer to the "+" means you're currently doing better than average, and vice versa.
