Originally Posted by johnnyszx5
It does not use odometer readings, trip or other to calculate mpg. It uses data from the ecm from injector pulse timing and probably some other data to calculate avg mpg. It is by no means precise but it is designed to be fairly accurate. In my old Ford truck forum the guys refered to them as the lie-o-meters. I am on the 5th tank of fuel at about 1700 miles and avg is showing 31.2. I hand calculated the last tank to 31.7. It took a while for the display to creep up to this point and showed consistently lower numbers for the first 4 tanks. The overall avg of all tanks show far calculates out to 33. I do about 25% highway and 75% suburban stop and go. Was hoping for a bit better but 31 is still better than 19 and I'm still pretty confident it will creep up some more, particularly if I can shave some pounds of my foot.
Thanks for the info, I was wondering how all this calculations was adding up.