Under certain conditions (e.g. tailwind, slight downslope, or slowly declining speed) it is quite possible to have the gas engine providing some propulsion, yet be getting more than 100 mpg. When that happens, the U.S.-market display is capped to 100. Therefore, a 100 mpg display is not a definitive indicator that no gasoline is being burned. Other country displays reading liters/100km will betray the real situation, as will a ScanGauge-II or other OBD reader that can display instant MPGs higher than 100.
Thanks for that, makes sense. I just bought one of those OBDII readers, gna use it with the torque app to see exactly what I'm getting.
