Why does the car shake severely when starting?

[StRowan]

The reasons for severe shaking when starting the car: 1. Engine mount issue: If the car shakes while idling in place, the engine mount needs to be replaced; 2. Carbon deposit problem: Excessive carbon deposits on the pistons or spark plugs can cause the fuel injected by the fuel injector to be absorbed by the carbon deposits during cold starts, preventing it from participating in combustion. This leads to incorrect air-fuel mixture, unstable idling, shaking, or even misfiring; 3. Incorrect air-fuel mixture ratio: This involves multiple factors, such as the atomization condition of the fuel injector, the ignition condition of the spark plugs, the data from the intake pressure sensor, the air intake data from the mass air flow sensor, the fuel pump pressure issue during cold starts, and the environmental temperature data from the ECU, all of which need to be checked.