Ok, so when it comes to fuel additives and the like, I am very skeptical. I seen video after video (from very honest, trustworthy people: ChrisFix, Engineering Explained) which all show no real, noticable improvement. However... My Prius was having a fuel gauge issue that started mid-2019. Basically, my fuel gauge would read 0 at about 380 miles. Given the fact that the Prius has an 11+ gallon capacity and an average MPG of 40, this is well below actual empty. Given this info, I simply stopped paying attention to the fuel gauge and went to figuring fill-ups as we do in the motorcycle world: gallons x low-ball MPG = estimated range.
Well, recently, Napa had a sale on some fuel injector cleaner so I thought "what the hell, it's only $5." I bought it, dumped it in at the next fill up and to my surprise, my fuel gauge didn't read empty until I hit about 430 miles on the trip Odo. I was shocked... Amazed... Dumbfounded!!! There was no improvement in MPG (I had actually hand cleaned the throttle body a few months prior) and the ICE ran the same as before but the friggin fuel gauge issue was fixed. I still can't explain it other than giving mad props to Lucas injector cleaner!!