What caused the serious engine jitter of Mazda 3?

The violent vibration of Mazda 3 engine may be caused by serious carbon deposition in the engine, carbon deposition in the injector and fault of the throttle position sensor.

When there is too much carbon deposit in the engine, the gasoline sprayed by the fuel injection head will be absorbed by the carbon deposit during the cold start, which leads to the lean mixture during the cold start and makes it difficult to start. It is not easy to enter the car before the gasoline absorbed by carbon deposits reaches saturation. After entering the car, the gasoline adsorbed on the carbon deposit will be sucked into the cylinder by the vacuum suction of the engine for combustion, which will make the mixture rich, and the combustible mixture of the engine will be diluted and concentrated, resulting in idling jitter after cold start.

Carbon deposition in the nozzle will cause different fuel injection quantity of each cylinder nozzle, resulting in engine jitter or blockage; When there is too much carbon in the spark plug, the spark plug will not work because of air leakage, and the engine will shake; Too much carbon deposition on the accelerator will also cause difficulties in starting, idling jitter and accelerated flameout.

Also check whether the throttle position sensor is working properly. At the same time, check whether the grounding is false.