What does it mean when the system is too rich at idle speed?

[McAnna]

The meaning of 'system too rich cylinder group 1 at idle' is that the vehicle's air-fuel mixture is too rich. Vehicle fault manifestations: When the mixture is too rich, gasoline leakage can be seen at the valve shaft, the engine lacks power, is difficult to accelerate, exhaust emits black smoke with a 'popping' sound, spark plugs have excessive carbon deposits, and in severe cases, the engine may stall automatically and fail to start. Fault causes: Air filter is too dirty or the filter screen is clogged; throttle valve is not fully open; improper cleaning of the main jet causing jet damage and increased flow; fuel leakage due to float rupture or improper sealing of the needle valve, leading to excessively high fuel level in the float chamber; poor sealing of vacuum or mechanical economizer ball valve causing fuel leakage, which increases fuel supply to the main venturi.