What is the cause of idling jitter of Ford Focus engine?

The engine has a serious carbon deposit, and the most common reason for car jitter is that the throttle is too dirty or the nozzle has too much carbon deposit. When there is too much carbon deposit in the engine, the gasoline sprayed by the cold start injector will be absorbed by the carbon deposit. The reasons for the idling jitter of Ford engine are as follows: 1. The engine has a serious carbon deposit, and the most common reason for car jitter is that the throttle is too dirty or the injector has too much carbon deposit. When there is too much carbon deposit in the engine, the gasoline sprayed by the cold start injector will be absorbed by the carbon deposit. 2. Engine lack of cylinder: Engine lack of cylinder mainly refers to the abnormal operation of one or more cylinders of the engine, which is characterized by obvious intermittence of the exhaust gas flow discharged by the automobile, so that people can obviously feel the jitter of the engine, sometimes accompanied by sudden noise. This is mostly related to the failure of ignition coil; 3. The combustible mixture of the engine is sometimes thin and thick, which leads to idling jitter after cold start. The lower the temperature, the more oil is needed for cold start, and the more carbon deposit will affect the success of cold start.