I've been watching the tank average MPG calculator from time to time, and it had looked pretty consistent. It changes radically when I first gas up, but starts to stablize (not change radically) within a few miles. But last night, with about a little less than 1/2 tank left, I stopped to pick up some dinner. When I started the car again about 20 minutes later, I noticed the Tank Average number started to change radically, jumping all over the place to the point I don't trust the reading it's giving, and it hasn't corrected itself yet.

Has anyone had this happen before? With this many electronics in this hybrid, I wonder if there's a button that keeps "resetting" the tank average calculator constantly that should only be "reset" when I gas up.

Thanks for your help.

I believe the tank average on the MFD resets itself when the fuel door is opened. You may try opening the fuel door to "reset" it and see if that works. I only use the tank average in the car to get an idea of what I'm getting. I've developed a spreadsheet that I populate every time I refuel to get actual MPG readings.