The idle speed of the car is shaking and unstable. What happened?

1. The engine has serious carbon deposition.

The most common cause of automobile jitter is that the throttle valve is too dirty or the fuel injector has too much carbon deposit. 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. In this case, only when the gasoline adsorbed by carbon deposits is saturated, it is easy to run into the car. After running into the car, the gasoline adsorbed on carbon deposits will be sucked into the cylinder by the vacuum suction of the engine for combustion, which will thicken the mixture and dilute the combustible mixture of the engine, resulting in idling jitter after cold start.

2. Ignition system problem

Check the working conditions of spark plugs, high-voltage lines and ignition coils. Poor working conditions of ignition system and spark plug can also lead to such failures.

3. The oil pressure is unstable

If the engine carbon deposit has been cleaned, the throttle valve has been cleaned and the spark plug has been replaced, it is still found that the car body is shaking at idle speed. It is recommended to check whether the oil supply pressure and intake pressure sensors are normal. If the oil supply pressure of the oil pump is abnormal or the value of the intake pressure sensor is wrong, it will cause the body to shake.

Solutions;

The best way is to clean the oil circuit, clean it regularly and use fuel additives such as PNF stock solution to solve the above problems caused by carbon deposition. The poor quality of fuel or the long storage time of newly installed fuel will lead to the rapid increase of colloidal components in the oil circuit, which will continuously pollute the fresh fuel, resulting in no good fuel to participate in the combustion in the later stage, and the carbon deposition exceeds the standard, especially for the national six cars. Only by maintaining a clean oil circuit can most problems be gradually alleviated.