What is the reason for the idle jitter of Ruifeng A60?

Vehicle idle jitter has the following common fault points: First, dirty throttle will lead to idle jitter. The second is that the spark plug does not work, which will lead to vehicle idling jitter. The third is that the engine cylinder does not work, which will also lead to idle jitter. There will also be vehicle jitter when the vehicle accelerates at low speed. Fourthly, the rubber parts inside the engine bracket and the gearbox bracket are aging, which leads to the vehicle idling jitter.