[99LeCouch]

I've been using Marvel Mystery Oil in my gas for the past 6 or so months, and have to say, it's made a bit of a difference in cold weather. The car's fuel system is quieter. The engine is knocking less, as seen on my ScanGauge set to display the timing pulled when the computer detects knock. Fuel economy data is unknown, but likely good. 33 mpg highway on my last big trip isn't too shabby, especially considering the 20* F weather the whole way.