When driving, you can display the mpgs on the cluster, and there is a little graphic bar below it showing you roughly how many mpgs you're getting.

Is everyone's bar showing 20mpgs while idling.?

 

Mines in storage but.. I think yes it does. It doesn't go to zero

 

I didnt expect it to go to zero, but full bar @ 20? Its basically telling me while idling its burning 20mpg's. I get 12mpg's while cruising. Why would it be 20 while idling. Not sure if thats normal.

 

Mine sits at about 5 MPG when idling...and before the engine is warmed up. Not sure how it could be anything other than 0, seems to be correct at all other times though.

 

Just ignore it. You didn't buy an Evo to hypermile it like a Prius anyway.

 

It is a simple calculation primarily based on fuel flow and vacuum (and odometer, of course). At idle you are burning the least fuel (max economy) but, like you point out - the 0 in the numerator for Miles/Gallon is still "zero MPG". Me? I ignore that information and focus on driving...