I thought I read something on MSN just a day or so ago (can't find it now) that said YOU are responsible to make sure you're pumping ultra low sulfer fuel in your truck if that's what it requires. The article said pump nozzles at the stations will be the same size (leads me to believe that both grades may be available simultaneously) and also that a single tank of low sulfer fuel will certainly damage the emmision system of the 2007 diesel engines designed to run on Ultra Low stuff.