Today , 55 deg F , and despite what Wunderground says , I had a good tailwind when I was headed east. Of the 35 miles I drive in the morning , about 18 are east and 17 north. 35.1 miles , 62.87 MPG. Tank is at108.0 miles , 61.57 MPG. I'm reluctant to change my fcd adjustment factor. We'll run one more tank , then decide. If it seems to stay 4.5% , I will use that. Much better than 7% ! Maybe it IS the fuel.