What does 99.9 MPG mean?

Yes, for that very short distance where your engine wasn't running. But the further you go the consumption will drop once the engine comes on etc.

 

You are actually getting more than 99.9 MPG. 99.9 is the highest number that the MFD can display.

 

it actually means nothing. but it is telling you that your engine didn't come on. you can't have mpg's without the g's.

 

This is not necessarily true. It is possible for the ICE to be running while the car is getting 99.9 MPG or higher. I have been driving while the MFD displays 99.9 MGP and Torque displays a number between 99.9 and 255 (which it the Torque maximum).

Agreed. If the ICE were not running at all, MPG is not measurable. At this point, the MFD would display 99.9 while Torque would display 255 MPG.

 

good point, i guess if conditions are right, it is possible. unfortunately, that would be the minimum, since it doesn't go any higher, and you might be getting a great deal more!