Fuel System Cleaners: Improve Engine Efficiency, Mileage & Longevity in 2025 Modern vehicles are designed to deliver consistent power, smooth driving, and low emissions. But even the most advanced engines face one major issue over time — residue buildup. Impurities in gasoline and diesel gradually collect inside injectors, intake valves, pumps, and the combustion chamber. This buildup restricts proper fuel flow, lowering performance and increasing fuel...