Thanks Jessekrs, so I would undo the 4 bolts and undo the hoses going in/out of the entire metal body that seems attached to the manifold?? (Picture above looks identical to mine)
I don't take the top yellow housing off but the actual entire metal piece as a whole??
Would I need any new gaskets of sorts before I go and do this to be prepared for that I can pick up at my subaru dealership tomorrow on the way home from work??
Take off this piece, check for it being gummed up with stuff, use brake cleaner and something that I can use to gently wipe / clean grime off from the inside I'm assuming of this casing and valve?