Is it possible that the abnormal sound of the automobile engine is the sound of the fuel injector?

1. The syringe does make noise when it works, but it is relatively small. Click on the description doesn't seem obvious, booing.

2. Spark plug misfire sound, which is at the same level as fuel injector working sound, also belongs to hissing sound;

3. When the throttle body is idling, the opening is small, and the airflow hisses like a whistle;

4. The PCV valve of crankcase ventilation hisses when working;

5, valve closing sound, the valve closing sound is relatively loud, and the sound will be more like a beep;

6. Valve train, especially one equipped with valve rocker arm, has a large cam clearance. If the valve clearance is large, the clicking sound will be obvious;

7. The belt is abnormal, with periodic clicking sound.

I can't think of any other possible noise for the time being.