93 Octane here is 3 bucks and went 20 cents higher over night. Tomarrow is supposed to be over 3 bucks for mid grade and there is rumor that the gas stations here are supposed to close for a few days because of the hurricane, etc down in Florida and the other places. I went to the gas station a bit ago and there were heaps of people there and said the same thing. :? I would run 93 octane and see if it knocks. If so then time it. If it still does then you will need to raise it.