I recently purchased a 2013 GMC 3500 diesel truck and on the dic it will give me average MPG and the owners manual states that instant mpg is available if so equipped. My question is is it a software...
I bought an OBD II scanner off E-bay. It connects to my phone via bluetooth. The phone is running "Torque" software and gives me all kinds of data like instant MPG. Pretty handy for $20 or so.