Cataclean 473ml Engine and Catalytic Converter Cleaning Treatment Using Cataclean can lower your total hydrocarbon emissions by up to 50 percent Reduces carbon build-up in catalytic converter, oxygen sensors, fuel injectors and cylinder heads which results in improved fuel efficiency Improves overall vehicle performance-including driveability issues such as power reduction, hesitation, rough idle, hard starts and lost fuel economy Safe for gasoline, diesel, hybrid and flex-fuel vehicles; does not alter fuel Not for use in 2-stroke or oil / gas mix engines