That partially explains why my mileage tanks in the winter time. I remove my tonneau cover and tailgate to keep them from salt exposure. Couple that with the "winter" blend gas and you have a gas mileage robbing hat trick!
2006 23B Hybrid with 10k round bar WDH
2011 F150 4x4 SCREW Ecoboost, Max Tow, Integrated TBC, 3.73 LS axle, Firestone Ride Rite airbags.