Fusion Energi MPG

Warranty?

Perhaps the fuel flow sensor has packed it in.

I live in Reno and the closest dealer that services the Energi is 120 miles away. Everything is ok except the readout. I only drive about 22-25 miles so I hardly ever use the ICE and am still on my 2nd tank of gas. My MPG display was creeping up every week and at about 5000 miles jumped from about 570 MPG to 999.9 and the efficiency leaves stay the same at full screen. I have tried the dealer's idea of reseting the trip and regular MPG to zero but as soon as I start driving the display jumps from 0 - 999.9.

Not sure about your leaves display, but the 999 for range may be because you have driven so much on battery alone, and not ICE. That estimated range is just a projection based on your previous driving. So if, for example, you've driven the last 500 miles on battery, and have enough gas in the tank to take you another 500 miles, the projected range would be 1,000 miles (or 999, since the range display can only go as high as 999, no matter what it is). I have a 2018 Fusion Energi, and my projected range, depending on how much gas I have in the tank, often is 999, because of all the battery-only driving I do. So my car's computer is projecting that I will continue to drive on battery only a lot, hence the almost unlimited range per tank of gas it estimates I will get. You could try disconnecting the regular (12-volt) battery for a few minutes, then reconnecting, and see if this would reset all the car computer's systems, including the gas mileage estimates.