upon second look, it's surging to about 2.1-2.2k at first, and then slowly the surge gets less and less and eventually does one final surge to about 1.5k and then gradually falls down to ~650RPM

 

also, i just went and bled it real quick, but that was before i read your note about the heater thing... if i didn't do that would it make a difference?

 

Yeah, you need to max open the heater lever to allow complete coolant circulation.

 

Alright, after looking at the coolant lines yea that makes sense. I always wondered what the smaller coolant line went to...

So actually, the line going from the engine, directly under the distributor, to some valve looking thing by the firewall (must be the heater valve?), and then the line going from that valve to the firewall, both are pretty worn and at that valve it looks like some coolant (very very very veryyyyy little) is seeping out.
I'm gonna replace those 2 hoses tomorrow (if advance or auto zone has them in stock) and then add coolant to the system and rebleed it.

Any idea what those 2 hoses are called (so I don't sit there at the auto parts store for 15 minutes trying to explain what i'm talking about)?

 

I think you're talking about the two heater hoses. Show them the diagram to avoid confusion.

 

just the longer one of the two heater hoses,
and then the other hose i'm talking about is there's a housing attached to the firewall end of that longer heater hose, and after the housing is another hose, that goes to the firewall. the last mentioned hose is the other of the 2 hoses i'm talking about. (it's not in the diagram)

 

Is the missing hose in this diagram?

 

yea there it is, the inlet side one

so i need both inlet side heater hoses. the one before, and the one after the heater valve

 

Trust, I think Florida and the Texas gulf coast probably have very similar climates. After I started my cold engine (2000 Civic) this morning, the engine idle speed rose to about 1800 rpm for 1-2 seconds, dropped to 1500 rpm, and very gradually decreased over the next several minutes to the normal warm engine speed of about 700 rpm.

 

just got done replacing those hoses. i filled the radiator back up, bled the system correctly this time, checked levels, added antifreeze to the reservoir... idle still surges.
I checked vacuum lines and they're fine
I think i'm just gonna not worry about it. It drives just fine and the surging goes away fast, so i think i'll just leave it at that.
At least I fixed a couple leaky hoses out of this whole mess

BTW, that clamp and hose on the firewall going to the heater is probably the biggest PITA i've ever encountered while working on a car. I had to cut the hose off the inlet with a utility knife, and it took forever because of how cramped the area behind the engine is. Not to mention it took 30 minutes to get the clamp off.