In July 2006, the automatic transmission Nissan Teana 2.5, and the idle speed was high after the throttle was washed. How to solve it?

Because there will be impurities in the intake process for a long time, these impurities will accumulate at the throttle for a long time, and then more and more carbon will be deposited. When the throttle valve reciprocates, it will be resisted for a long time, so the engine computer will adjust the position of the throttle valve. 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.