^ Cleans fuel injectors, intake valves, and combustion chambers. ^ Can be used as often as 3,000 miles or at every oil change. ^ For use in all gasoline engines (MPI or GDI systems). ^ A 20 ounce bottle treats up to 20 gallons of gasoline. Hyundai Fuel System Cleaner Plus (P/N 00232-19047) is now the approved and recommended service product for complete fuel system cleaning during routine service and preventative maintenance. Hyundai does recommend the use of fuel system cleaner Fuel tank additives won’t clean the intake valves in direct injection engines.