I'm no mechanic. I recently bought an '87 TA with a carb. 305 that is all original. Recently, when it is cold, the engine idles extremely high -- when I get to a red light, the brakes are just holding it back. If I stop somewhere and put it into park or neutral, the engine is over 2000 RPM. When I go to shut it off in this condition, it wants to keep running.
I'm just kinda looking for some ideas before I go under the hood and start making things worse.
Oh, let me add to this. It recently had the exhaust replaced and the cat removed. Could this have something to do with it and, even if so, what can/should I do...

 

Most likely something is amiss with the choke. Either the vacuum choke pull-off pot isn't working right, or the electrically heated choke thermostat isn't working for some reason (like the power wire came off).

If the exhaust replacement didn't involve working around the top of the engine, it mostly likely isn't related.