What causes unstable idle speed fluctuations in the new Santana?

[LeTaylor]

The reasons for unstable idle speed in the new Santana include excessive carbon deposits, fuel supply system malfunctions, and cylinder misfires. Excessive carbon deposits: Severe carbon buildup in the engine cylinders can lead to clogged spark plugs and valves, directly causing the car to shake during idle. Normally, carbon deposits should be cleaned every 40,000 kilometers at a maintenance facility. Fuel supply system malfunction: Unstable fuel pressure can easily cause fluctuations in the concentration of the air-fuel mixture, resulting not only in shaking but also unstable idle speed. Consider replacing the fuel filter first, followed by cleaning the entire fuel system. If necessary, the fuel injectors may need to be replaced. Cylinder misfires: If the ignition coil malfunctions or the spark plug fails to fire for some reason, shaking will occur. The normal lifespan of spark plugs is 40,000 to 60,000 kilometers, while ignition coils last 60,000 to 80,000 kilometers. Remove the spark plugs and check for carbon deposits and signs of erosion at the top. Replace them if necessary.