Here are the specific reasons why a new car shakes after starting: 1. Suspension system failure: The suspension system is mainly responsible for filtering the vibrations from the engine during operation. If there is a problem with the suspension, these vibrations will be directly transmitted to the steering wheel and the cabin, affecting driving. When the engine is idling, turning on the electrical systems inside the car can also easily cause shaking. The engine increases its load due to the electrical systems being turned on, causing the idle speed to drop. To compensate for the shaking caused by the drop in idle speed, the engine will automatically increase the RPM. 2. Unstable oil pressure: Check whether the fuel supply pressure and the intake pressure sensor are normal. If the fuel pump's supply pressure is abnormal or the intake pressure sensor's readings are incorrect or malfunctioning, it can cause the car body to shake. 3. Cold start: The main reason for shaking during a cold start is incomplete fuel combustion, which results in insufficient power. The ignition energy is relatively low during startup, and when the temperature of the fuel and lubricating oil is low, more fuel is needed to meet the power demand. Over time, the gap at the spark plug's electrode gradually increases, leading to a decrease in ignition energy and poor fuel atomization, which causes the car body to shake. Additionally, aging ignition coils, aging high-voltage wires of the spark plugs, or leakage can also reduce ignition energy.
