Flow enhancer is a substance that prevents a fuel from getting viscous or saves it from partial freezing. In very cold countries or at high altitudes fuels have increased viscosity. This prevents them from flowing properly. Fuels which have thermal-oxidative are less prone to all this. But these fuels are very costly so help of flow enhancers is commonly taken. These also perform the task of removing deposits in combustion chambers, intake manifolds, ports, on valves etc. first-rate products do this job swiftly, safely and in detail. Their use improves fuel economy and lessens exhaust emissions. Taiwan, USA and China are the major manufacturers.