I have noticed that the MPG and Range do not agree with each other. For instance I had 15 MPG at quarter tank I then filled the tank and reset the MPG gauge and was getting ~23 MPG. The Range reading changed to a higher number but acted as the car had a full tank but still 15 MPG. I drove for a while to see if the Range jumped but it stayed pretty constant.


Do I need to possibly reset the ECU?

 

Nope, the range changes instantly whereas the MPG is based on the time when you last reset it.