Over the last two weeks, I think I’ve read about every forum post on fuel additives in existence. Yet, I’ve never seen a question or an answer that addresses one specific aspect. All of the reputable fuel additives (or at least the ones that everyone seems to use) seem to be meant for periodic use, usually right before an oil change. What I am interested in is just the freedom to go to any gas station and it not be a problem if the gas happens not to be Top Tier. I had two Shell stations between my house and work, and they just replaced them with Casey’s. Plus it just makes sense to me that adding the right amount of detergent during every fill up is a better way of preventing carbon buildup than trying to clear up carbon buildup and also hope one application provides 6-12 months of protection. This question wouldn’t be applicable to anyone that has no trouble with access to Top Tier stations, but I’m hoping someone has run into the issue of not having easy access to good Top Tier gas and found a solution that allows them to pour into the tank at every fill up that essentially makes gas from a place like Casey’s have the same quantity and quality of detergents as gas from Shell or Chevron; nothing more and nothing less. I say “nothing more” because my owner’s manual says “does not recommend the use of any aftermarket fuel additives (for example, fuel injector cleaners, octane booster, intake valve deposit removes, etc). Many of these additives intended for gum, varnish or deposit removal may contain active solvents or similar ingredients that can be harmful to the fuel system and engine.” I realize that would suggest my question has no solution, but I’m hoping someone knows of a solution that literally adds nothing more than the fuel additives that than a Top Tier station would have, so I guess the unicorn I’m hoping exists is a fuel additive with high quality detergents that doesn’t contain any active solvents and is intended (and priced) to be used with every fill up. Many thanks in advance for taking the time to read this long post!