What does this tube do?

[mohammad]

Do you mean block the air intake side rather than the engine or valve cover outlet?

You are correct, thank you, I confused the two.

[nimas1377]

So after all these time I finally tested my pcv valve with a balloon and found interesting results like the car the pcv valve sometimes let the air leak when connected to an inflated balloon so I think the pcv itself is the problem. BTW while reversing today I recorded with an obd scan tool that my rpm drops to roughly 523RPM and the engine started shaking and then corrected itself. it happens both while driving or reversing but not always it sometimes happens