just did a smoke test on my 986S to trouble shoot codes p1128/p1130. found a small leak coming from cracked vacuum line fixed that, codes continued. did another smoke test and found smoke coming from the valve that sits on top of the resonance tube. I am not familiar with the function of this valve. is it a one way valve? ie. it blows out but not in? I did the test with the engine cool, is that valve only closed on a hot engine? should I being doing the test on cool or hot engine? also, is that valve safe to block off to see if that is what is causing the codes? would like to verify that before dropping $$ on a new one.