The major symptoms of contamination of the fuel system are: failure to start the engine; a noticeable power loss if the start is successful, especially during acceleration; engine malfunctions; increased fuel consumption. The most common way to flush the engine fuel system is to add a special flushing fluid to the fuel tank and continue operating the vehicle. The service stations use another cleaning method, which involves using a high-pressure cylinder, into which the solvent is poured. The procedure implies the use of the flushing fluid in the engine operation. It is also possible to remove and wash all the elements for the fuel system flushing purposes. The method is selected depending on the degree of contamination of the system.