[Coan]

Update: I pulled the intake manifold off to begin replacing all of the vacuum lines. They are all very hard and brittle and I found a few cracks in some of them, but that may have been from removing the manifold. After seeing the condition of these hoses I am pretty confident this is my issue. I also replaced the PCV valve and will be replacing a few other things while I'm in there.

Unfortunately I broke one of the plastic nipples on the black plastic "mystery box" while removing a vacuum hose. At nearly $60 I think I'll just repair mine...but I will need to order a new IRIS check valve as that has a crack in it...