i am confused, yesterday i replaced the plenum gasket along with the intake manifold gaskets and i still have the same vacuum leak that i cant find, when i get on it, my vents goto defrost and it sounds like ****

i have checked all the lines and the check valves and i dont know what else to look for any suggestions

 

If you have cruise control che the lines to it under the battery if you haven't.

 

there is also a vacuum cannister underneath the plastic cowl thing.
you might need a hand operated vac pump with a gauge. it lets you test individual lines. about $15-20 at cheap places like harbor freight.

there are 2 of those check valves. forget testing, i'd replace them both.