I usually use the Gumout "xtra". I doubt the stuff you add in the tank cleans as much as we would like but a good example would be a cousins 88 Ranger he bought years ago. It wouldn't idle for long periods of time. Sometimes it would die after a few
seconds@idle and other times it would run 3-4 minutes although rough. I gave hime a bottle of the cleaner one day and told him it may help or may not. He came back a few days later and said the truck hadn't quit once since running through his last tank of fuel with the cleaner in it.
