The Explorer is a completely different ball of wax when compared to the SHO in the OP. We really should keep the two separated. Even you cannot argue that the fuel that is available in the winter months is inferior in quality to what is readily available throughout the remainder of the year. With all of the other additives how do the law of thermodynamics not apply anymore? Things like E85, E10, C4H10 and other fuels all have different chemical properties, and these would obviously lend to different reactions. These differences WILL lead to quirks in performance VS the warmer months.