Marvel Mystery Oil (32 oz) is a multi-purpose engine and fuel system additive that helps clean and lubricate fuel injectors and carburetors while reducing gum and varnish buildup. Added to engine oil, it helps prevent valve sticking and clatter, reduce sludge formation, and support engine performance in extreme temperatures. It is formulated for use with catalytic converters and oxygen sensors. Choose your preferred option from the available pack sizes.