What's wrong with the exhaust emission of Chevrolet Cheng Jing?

Three-way catalytic converter is possible ... but there are other possibilities ... it may be that the throttle exhaust vacuum tube falls off. The throttle sensor is short-circuited, open-circuited or not connected ... It is also possible! ! See if the gasoline is normal ..! Gasoline trap .. clean the throttle! Carbon deposition and so on! ! ! ! Cheng Jing is not an old car .. The above may be caused by these reasons! !