geabis

I would have to say that it is the winter blend. Cooler air intake will make more power bc of the denser air and basically balance out bc it takes more gas to run the denser air mixture but the result is more power so I doubt you would see an efficiency difference. Tire pressure would be an area I would look at. Under inflation makes more rolling resistance. Up here in pa we run winter blend from the beginning of September to the end of may. And it makes for a 1-2 mpg difference. And defiantly give a sluggish feel.

MRigs81

In the last 2 days I drove from Richmond, Va to Lancaster, Pa and back. Temps were between 55 and 65. I was getting 20.7 on the way up an 21.5 on the way back down. I was quite impressed because I was running about 75mph when I could. The other part that I was impressed about was all the damn traffic I fought with stop and go on the interstates and beltways.

rancherlee

I've notice my mileage isn't the best until my tranny warms up above 120*F. Hopping on the highway on a cool 30*f morning it took me a good 20 MILES to get up to 120*f on the tranny. I reset the MPG on the dash and was only averaging 16mpg up to that point, once the tranny got up to 120*f the mileage started climbing and settled in @ 19mpg crusing 75mph My Fusion is the same way, cold start winter mornings drop my MPG atleast 3-4mpg, some nice -10* mornings my tranny never warms up enough to lock the converter on my 12.5 mile work drive!