I've noticed since Sept that my gas mileage has been getting worse. I drive down this big hill every day to work and during the summer when coasting down this hill (w/ foot off gas) I would actually pick up speed. For the last couple of months now coasting down this same hill, i actually start to slow down. Could the cold weather be having that much affect on my lube/bearings? Is something else going on here? I'm experiencing the same thing with my Tundra (although that beast never picked up speed going down hills).