Whew! Lots of stuff. So I was poking around over the weekend and did the old "push the EGR and the engine will stumble" only the engine didn't stumble. So I take it off figuring it's maybe clogged. It's not. I put it back on and start up. Still no reaction when it's pushed. Maybe the pipe is clogged? I undo the pipe with the engine running. Plenty of exhaust. Thread it back in and I thinks "maybe the internals on the common chamber are clogged". So I take off the EGR valve, with the engine running, and... no reaction at all. The engine continues to run.
I can feel the exhaust gas coming out of the upper port where the EGR is bolted up and I figured the lower port would be hissing from vacuum
(assuming it didn't stall out altogether) so I'm a little bit mystified at this turn of events. I shot the upper and lower ports full of carb cleaner with no change.

I recently replaced all the gaskets on the intake side (figuring that the low idle was because some busted gasket with a vacuum leak I hadn't found...it wasn't). I guess I'll have to get another set for the common chamber and take it off again. The only thing I can think is the gaskets
set I bought covered up some port that wasn't meant to be covered. So
presuming I get that working again I'll go down the list of suggestions and see if I can solve my low idle problem.