AMSOIL P.i. is a potent gasoline performance improver with a concentrated detergent that aggressively cleans stubborn, power-robbing deposits from injectors, valves and the combustion chamber. Effective in port and direct injection systems. Bottle compatible with capless fuel systems. Cleans the entire fuel system in one tank of gasoline. For use with cars and trucks. Treats up to 30 gallons. Add the entire bottle of 355ml to the tank at fill-up. For best results, clean your fuel system with P.i. every 4,000 miles (6,400 km). Do not use diesel or two-stroke engines.