Ok how can i explain this, you know how a free flowing exhaust sounds when the fuel is burning out of the pipe that vibration sound, when you let go of the gas, well whenever i step on the gas i get the reverse effect aswell, i here the same sound in the engine compartment it happens when my revs are climbing, it goes along with a deep hallow sound, what is it??

 

Intake noise is what I suspect.
Do you have an aftermarket intake?

thesaint

 

I just have a knn filter in the stock air box