What causes a Chery QQ to stall when decelerating to idle?

[EmersynRose]

The reasons for a Chery QQ stalling when decelerating to idle are as follows: Carbon buildup on valves and combustion chambers: Due to the characteristics of fuel-injected engine control, each time the cylinder operates, fuel is injected first and then ignited. The fuel injected during the operating cycle cannot be recovered and instead adheres to the intake valves and combustion chamber walls. While gasoline evaporates easily, the wax and gum substances in the gasoline remain. Over time, these wax and gum substances accumulate and thicken, hardening upon repeated heating to form carbon deposits. Carbon buildup in the intake manifold: Carbon deposits roughen the walls of the intake manifold, causing turbulence in the airflow at these rough spots, which affects the intake efficiency and the quality of the air-fuel mixture. Additionally, carbon deposits can block the idle channel, causing the idle control device to stick or operate beyond its adjustment range. This can lead to low idle speed, idle shaking, failure of various accessory devices to accelerate, stalling when decelerating, excessive exhaust emissions, and increased fuel consumption.