I recently bought a 2013 Ford C Max and was reasonably pleased with the 34.5 MPG that I was getting. I took it in for a software upgrade and the mileage jumped to almost 45 MPG which is more in line with the C Max ratings. This mileage rate continued for well over a week, but then over the next couple weeks, the mileage has slipped back down to around 38. I was just wondering if the upgrade truly increased the mileage, or was it just a distorted reading based on a "reset" of something. I think the >40 MPG was real as I partially confirmed it via fill up gallons and mileage driven. Is there any way to keep the mileage at almost 45 MPG?? Or is there some parameter being set and charging too aggressively damages the battery???
This also begs the question - are there any after market programs that increase mileage? I am sure that this would not make Ford happy, but just asking for now. BTW, the SYNC system does out right stink. I am seriously thinking about getting a separate blue tooth speaker / etc. instead of using the car's.