i believe he was referring to the description of your mystery "black" box. is this the black box that's visible from the top of your engine or the black box behind the intake manifold?
the black box on top, driver side is probably your cruise control. the other black box deals with vacuum..i think it's your EVAC tank... i keep forgetting the proper name.
don't worry, it's probably an old cracked hose that needs some TLC. get underneathe the car and trace it back.