The idle speed of the old Lexus is200 reached 2000_3000. How to solve this problem?

The idle speed of the old Lexus is200 reached 2000_3000. How to solve this problem? Cold start, the three-way catalytic temperature is not enough, and the engine is seriously carbon-deposited, which causes the car to shake. The most common reason is that the throttle valve is too dirty or the nozzle has too much carbon deposit, because the gasoline adsorbed on the carbon deposit after the car is sucked into the cylinder by the engine for combustion, and the combustible mixture of the engine is diluted and concentrated, which leads to idling jitter after cold start. Solution: The company cleans the oil circuit, and checks whether the idle motor has carbon deposit, so it should be cleaned.