Brandi, My understanding is they dont make the "4C" any more and it was more used for a combustion chamber cleaner, similar to Seafoam. Being it was the weekend, no way to get filters.
I will try Cummins in Ft worth. I want to change the oil filter also, I dont know what it is and if fuel has been able to bypass the cylinders to the oil. I will also get a fuel filter, but will likely try to use up this tank of gas unless forced to change it 1st, No telling what residues where/are in there!! Manual has first oil change at 20 hrs, but you know how that goes on an engine that has mostly sat there!