[Christ]

I threw a gallon of Xylene (117 Specific octane, pump method) in with 11 gallons of 87 gasoline on a few fillups... it didn't do much for gas mileage, at least it wasn't detectable in my car with my driving habits, but I did notice afterward that the intake noise had changed... that said, I removed the intake manifold to swap up to MPFI fuel system, and found that the intake runners were squeaky clean, which is exactly the opposite of how they were when I installed this engine in this car.

Stuff in bottles is completely misconceived... if it says it raises octane 3 points, it does just that... 91 becomes 91.3, not 94. Simple math figures these things out. *they also say so right on the bottle*

Look at the ingredients in most additives.. you start to see the same thing over and over again... MTBE, Xylol, Toluene, MEK, Ester, etc... see what they're doing? Add an extremely high octane component in small amounts, and it does change things somewhat, but these things are already in your fuel to begin with.. so they're not some "miracle blend" of additives. Most of them are crap.

Use common sense... if something claims to clean your choke and throttle body, yet you dump it in your gas tank, it's not going to work... your fuel never touches your throttle body or choke on FI vehicles.

By the way, the only reason most of those additives are still around to deliberate about is because people still see a purpose to them where there is none. In most cases, you're adding gasoline's components to gasoline... only you're paying more for the same thing you already had.

There are very few that actually do anything, Lucas, SeaFoam, MMO, etc... these are the ones that have been around for decades, and even they only work when USED CORRECTLY.