Many, many years ago, I tried a somewhat similar product. It came in caplets, one caplet per each 10 or 12 gallons. And something like $1.50 a caplet. Discounts in larger quantities.

The claims were quite similar, even the fact that "you will start to see a slow improvement, usually by the 3rd or 4th gas tank".

The results?? In a single word: mixed. Sometimes I did see 25% MPG improvements, sometimes negligible. Never really understood why, other than I was then working as an independent contractor driving lots of city miles, and my daily driving routine was always different.

I also remember that I felt a more responsive engine, but that could have been a placebo effect.

The U.S. has reached a point “where the priorities of Congress could become so distorted by politics” that it would turn its back on the next great global industry, clean power — Rhone Resch