Home›Products›Engine & Fuel Systems›Fuel AdditivesFuel AdditivesWant to maximize fuel efficiency and avoid problems such as rough idling, weak acceleration, stumbling and stalling? STP® fuel additive products can help.Product Category Please selectEngine & Fuel SystemsFeatured ProductsFunctional FluidsMaintenance & OtherProduct Type Please selectFuel AdditivesMotor OilMultipurpose AdditivesOil & Engine AdditivesSort by Please selectA to ZZ to ASort by Sort byA to ZZ to AFilterFilterProduct Type Engine & Fuel Systems Featured Products Functional Fluids Maintenance & OtherView ProductsView ProductFuel AdditivesUltra 5-In-1 Fuel System CleanerView ProductFuel AdditivesSuper Concentrated Fuel Injector CleanerView ProductFuel AdditivesGas TreatmentView ProductFuel AdditivesComplete Fuel System CleanerView ProductFuel AdditivesOctane BoosterView ProductFuel AdditivesHigh Mileage Fuel Injector & Carburetor TreatmentView ProductFuel AdditivesAll Season Water RemoverView ProductFuel AdditivesSuper Concentrated Gas TreatmentView ProductFuel AdditivesRacing Series Octane BoosterView ProductFuel AdditivesHigh Mileage Complete Fuel System CleanerView ProductFuel AdditivesFuel System Cleaner for EthanolView ProductFuel AdditivesDiesel Fuel Injector TreatmentView ProductFuel AdditivesDirect Injection Fuel Injector Cleaner