Let me start off by saying I keep track of mileage thru an app so it is calculated correctly. Over last 7k I was averaging 21.8 mpg and that is a mix but last tank was terrible at 13.4 mpg all low mph with plenty of stops and idling. My lie o meter was at 15.3 but hasn't been reset in I don't know how many miles cause I never looked at it. So I hooked up the Bluetooth app to run a fuel consumption test confirming my thoughts. I had to go to the store which is 11 miles away. I wound up with 16 mph average, 14 mpg on the way there and dash stated 15.3. On the way back I decided to use econ button to see if it makes any difference. The results surprised me as on the way back (same speed, route etc) mileage climbed to 19.8 mpg. Hard to believe that in town with Econ button on I gained almost 5 mpg. The dash even climbed to 16 mpg so it definitely helped and still haven't reset it as I don't trust it. I appreciate any thoughts or experiences that you have.