The reason for the engine vibration of a car is: 1. The engine throttle is too dirty or the fuel injector has too much carbon accumulation. The gasoline sprayed by the cold start fuel injector will be absorbed by a large amount of carbon accumulation, causing the cold start mixture to be too lean and difficult to start; 2. Poor operation of the ignition system for spark plugs, high-voltage wires, and ignition coils; 3. Abnormal fuel supply pressure, incorrect intake pressure values, and poor sensor operation. The solution to car engine vibration: 1. Clean the oil circuit, check the idle motor, and clean carbon deposits; 2. Check if the spark plug has too much carbon buildup and replace the spark plug; 3. Check the oil pressure and replace the components.