Why does the engine idle after the throttle of Teana engine is stuck?

The engine has serious carbon deposit, the throttle is too dirty or the injector has too much carbon deposit.

There will be impurities in the intake process, which will accumulate at the throttle for a long time. Over time, more and more carbon will be deposited. At the throttle, there will be resistance when reciprocating. If this situation persists for a long time, the engine computer will adjust the position of the accelerator pedal. That is to say, the position of carbon deposition is regarded as the ontology, that is to say, the throttle valve is not at all but near the position of carbon deposition.