I have had my truck just under 3 months and now have 7800 miles. I'm getting between 17.5 and 16.5, manually calculated, overall with 80% being interstate at 70 MPH. Before it cooled off those numbers were almost 1 mpg higher and I've always had the same results of lower MPG in cooler weather on other vehicles as well. I had something interesting occur on my last fill up. EVIC was saying 15.1 average mpg which is the lowest I had observed and I attributed it to headwinds all week long, swear it changed midday
. However when I filled up it calculated out to 16.8. Usually it would show higher, calc lower. Just found that interesting.