Protect your expensive fuel injection and restore lost power. Recommended by Bosch, Swepco 503 Fuel Additive breaks down impurities and particle build-up that cause engine performance problems. Since Swepco 503 emulsifies water, regular use prevents corrosion and particle build-up. Use one can every 2 or 3 tankfulls. We also recommend occasional use in carbureted engines. 12 oz