What are the symptoms of car carbon deposition?

The car has carbon deposition symptoms: 1, the cold car is not easy to start after repeated ignition, and the hot car is normal; 2, the engine idle speed is unstable, high and low; 3. I feel that the acceleration is not smooth when I add empty oil, and there is a sense of tightness; 4, driving is weak, especially when overtaking, the speed response is slow, and the original vehicle power cannot be achieved; 5. The tail gas is dazzling and pungent, which seriously exceeds the standard; 6. The fuel consumption is higher than before. Methods of cleaning up carbon deposits in automobiles: 1. Adding fuel additives to fuel to improve the combustion effect of gasoline; 2. Maintain the engine regularly; 3. Change the oil regularly; 4. Regularly clean and maintain the oil circuit, spark plug and throttle.