What are the main reasons why cars don't idle?

The engine starts normally, but whether it is a cold engine or a hot engine, the idle speed is unstable, the idle speed is too low, and it is easy to stall.

Second, the reasons for the failure

1. Air leakage in air intake system or vacuum system.

The air filter is blocked.

3. Idle speed control valve or additional air valve is not working properly.

4. The air flowmeter is faulty.

5.EGR valve is stuck in the normally open position and cannot be closed.

6. Improper idle speed adjustment.

7. The oil circuit pressure is too low.

8. The fuel injector has poor atomization, oil leakage or blockage.

9. The spark plug is defective.

10. Leakage or open circuit of high voltage line.

1 1. The ignition timing is not accurate.

12. Cylinder compression pressure is too low.

I hope I can help you! ! !