Tiggo 5 has a slight abnormal noise when idling. What is the reason for the great god?

The reasons for the loud noise of automobile engines need to be investigated from the following aspects: 1. When the car is idling, open the front cover and suspect that the car engine has abnormal noise. If you can't hear the sound in the car, it's not too loud. It is usually the sound of a valve or an injector. The carbon canister solenoid valve also has this sound, but the sound is brittle. There's a way to tell the difference