Ford Repair: 01 Ford Ranger 2.3 Running Rough, flange bolts, exhaust flange

Question
There was no place to enter a follow-up question following your last response. I checked all the vacuum lines and couldn't find any other leaking. I sprayed WD40 all over and there were no changes in idle unless I unplugged the dangling line on the passenger side. I looked around and it seems to have gone to a plastic cylinder attached next to the radiator that looks like it may be part of the fuel vapor system. I reconnected the line and it ran worse, so I replugged it. I can't get the exhaust flange bolts loose. Is it better to try when the pipes are hot or cool? I'm using a 1/2 drive breaker bar and I'm afraid I'll break them.
The engine does not want to run above 3000 rpm when you rev it in neutral. I read somewhere that running rich for a while will plug up the catalyst, so that is probably part of the problem. But I guess I need to find what made it run rich.

Answer
if you open the hood of your vehicle. on the hood there will be a vacuum diagram of where that line leads, you are correct that a rich condition will damage the cat. if the vacuum line is disconnected, uncontrolled air will enter the engine, the computer will naturally dump excess fuel to try to compensate. read this diagram on your hood, it's pretty fool proof to see where it goes