Has anyone used marvels mystery oil as a gs additive? what does it do? how does it work?

 

Yes. I have used it as a gas additive. I have also used it as an oil additive. First, the good: As an oil additive I can't praise it enough. My truck (2001 5.4L F150) had 125,000 miles on it and suddenly started blowing blue smoke on start up. I immediately thought valve seals but that couldn't have been it because I was going through a quart of oil every 300 miles ! Valve seals wouldn't cause that kind of consumption. In my mind, I was looking at an engine rebuild. I was sure it was rings. Then my nephew, a diesel mechanic, said "Before you panic, put a quart of MM oil in it." Low and behold, after 1,000 miles, blue smoke was gone and I now go though zero oil, like I was before the incident. I now ad a quart of MM oil every other oil change. I have 165,000 on my truck now. I never did find out what caused the blue smoke but at least it's gone. And $5 sure beats a few thousand for a rebuild. Probably a stuck ring or something. Ok, now the bad: I used it once as a gas additive and a week later my truck would not idle. It kept dying. Come to find out the IAC valve (idle air control) was gummed up. I replaced it and all is well. So, I no longer use it as a gas additive but I continue to use it as an oil additive. BTW, I have Blackstone Labs do an oil analysis every other oil change and the reports always come back with comments like "This oil looks like it came out of a truck with less than 20,000 miles on it. Whatever you're doing, keep doing it."

 

As a gas additive? Never used it for that, always used seafoam or lucas.