I took a road trip in my Prius v yesterday and (not too closely) tailgated some semis for a good portion of the 240 miles. I had around 200 miles on the tank when I started and the average mpg reading was around 48.8. Over the course of the trip, the average mpg reading slowly crept up and by the time I got off the highway, it was reading 50.3 mpg. I drove probably 3 miles to a gas station and filled up, not doing anything special to lower my mileage. When I got to the station and filled up, the average mpg had changed to 47.7 mpg. I cycled through the readings again, and it went back to 50.3. I did this a few more times and got several of both readings again. When I filled up, based on the odometer and how much fuel I put in the car, my actual mpg was 46.8. Not a problem, but interesting.
One way to reset the average is mess with the History screen, I try to never go there. While my 'lifetime' (see above) average is 42.0, my fuelly average is 40.4
....I've also been watching my Gen2 MFD it can be on say 55 MPG after a highway trip 100 miles and next day a short trip or two it'll be down below 50 in no time.
Be aware that the displayed average is dependent on the displayed trip meter or odo, its supposed to change. If you reset the history screen, the odo MPG reading will also change.
I found out the hard way that hitting update on the history screen also resets the "lifetime" MPG associated with the odometer. So be aware. Nickster4, could you have been looking at trip1 at 50.3 and trip2 at 47.7 as you scroll through trip1, trip2, and Odometer readings?
Nickster4, I been noticing the same thing. I exited off the freeway at avg 53. EV kicked after the stop light, travelled a couple of miles then the avg dropped to 52. Came to another stop light, Pulse and Glided for another mile then avg dropped to 51. Parked with a avg reading of 51. In the process of creating a snap chat to my friend, who's thinking of getting a Prius, my avg dropped to 50. Wondering if the calculation is based off of an Algo that factors in Gas/EV/Time.