Average Mpg Resetting Its Self

[The Cav]

every so often ...not when refueling the tank

the average mpg reading resets itself back to zero and then starts

recalculating.....esp when the temp is warm outside

anyone else had this issue

[alan333]

Mine resets if I park the car on a hill. I guess the car thinks I've added fuel? Perhaps yours is the same.

[Thermal]

Normally, there's a vacuum inside the fuel tank.

Could be that the ECU senses that the vacuum disappears when the filler cap ring is leaking, and resets like when the cap is removed for refueling.

Just a thought.