Scotty I bought 3 cans Gumout MST-UP for 3 different vehicles. Poured 1 can in my truck today and put 21 gallons 87 octane shell gas. I mostly use shell gas than anywhere else. Would u recommend chèvron over shell or vice versa?
Also added a can of berryman b-12 last week to my truck and it definitely made a difference in the way it was rough idling. I don't know how the gumout will work out but I now believe in the berryman tune up treatment.