Berryman B-12 CHEMTOOL TOTAL FUEL SYSTEM CLEAN-UP (part #2616) is our strongest detergent-based gasoline additive and will thoroughly clean dirty fuel injectors, intake valves, and combustion chambers, and one bottle treats 16-21 gallons of gas. It also eliminates “octane creep,” a scenario where carbon buildup in the combustion chamber causes the engine to knock/ping at octane levels it previously ran well with. 2616 should be used every 5,000-10,000 miles. If you want to know that you’re starting with a clean fuel system, then we would recommend starting off with a can of 2616 at 1 oz/gal. After that, start using the Berryman B-12 Chemtool Fuel Injector Cleaner (part # 0116) every third tank for great keep-clean performance. 0116  is an excellent preventive maintenance product for fuel injectors, carburetors, and intake valves.