There is a small black plastic box (4in x 2in) under Intake Manifold where 3 lines connecting in. I was told this is something to do with oil. One of the lines disconnects all the time i hit full boost (when oil pressure hit max.) and tons of oil squirt around the engine area. Did anybody have the same problem? What to do then? The lines has rubber end (or something) and i can not fix it there.

 

what application?

sounds like part of the pvc system, another one is most likely part of the charcoal canister for fuel vapors.

 

EDM 1.6VTi (B16A2) Civic

 

Oil seperator.

 

seems like either boost is going into your oilpan...worn rings or the one way valve inbetween the hose from that box to the intake manifold doesn't work and boost is going thru the hose.
If it's the side connected to the manifold that gets loose...just tighten it with a clamp.