Help! Super high & erratic idle, took stuff apart, put it back & now this Options

[GriffGirl]

Today I pulled off my throttle body and intake plenum; when I replaced the TB I replaced it with another one I had because I made it shiny

I'm fairly certain I've got all the vacuum hoses connected properly, and I don't hear a vacuum leak at all, but when I start the car now the idle rapidly fluctuates (like, BOUNCES) between 1500 & 2000 RPMs.

When I swapped TBs, I had to move over the TPS from the old TB, but the swapped one had the EGR valve on it so I left it. I'm wondering if this could be because now the TPS needs to be adjusted? Or is it due to a faulty EGR valve? I'm not getting a CEL either way, but I haven't actually driven the car, just started it up a few times now.

I'm thinking I'll just put the old TB back on as a matter of process of elimination, but if anyone has any thoughts as to what the deal is, feedback would be much appreciated.