The octane, I drained the tank recently to see if there was any phase separation or other issues. No issues found. I did find about a half tablespoon of fine black "dirt" floating in the bottom of my drain pan. This was the first time the fuel tank has been drained in a 19 year old car. It has never had sea foam or any other water treatment. I did find some water in my fuel filter when I changed the origional filter a few years ago, before I started spiking the fuel. I recently looked at the filter and there was no water. Unless you have large amounts of water, the ethanol should absorb it and allow it to pass thru the system. Ethanol may also break down varnishes and clean out your fuel system. While this is occuring you should keep an eye on your fuel filter for clogs.
