20 1 1 Duke Teana's fuel consumption is increasing gradually. What happened? It is now 15.3.

My Duke of Teana 20 1 1 current consumption 10.3, last summer was 15. Later, after asking and consulting, there may be these points! The injector is dirty, and there is a lot of carbon in the engine! The throttle is dirty! The reason is that the sprayed engine oil does not have enough air to participate in combustion, and the excess engine oil will be adsorbed inside the engine. After gasoline is burned at high temperature, some components in gasoline will become carbon deposits and remain in the engine due to insufficient combustion. Carbon deposition is more and more insufficient, and carbon deposition is more and more due to insufficient combustion. This is a vicious circle.