I bought some of this off ebay. And added it to my gas tank when the level was down to 1/8 tank at the beginning of June. After 60 miles of in town driving the needle on the fuel gauge just moved off the full mark. This is in my little 4 cylinder runabout with 114k miles on it.
Here is a video I found on youtube of a guy doing a test on his car with it.
Here is a video I found on youtube of a guy doing a test on his car with it.