PCV valve replacement & engine loping

Can anybody give advice on replacing the PCV valve on an 89 MGM?
I have the new part, but it is in such a hard place, I can't seem to get to it.

Also, I was looking for advice on the engine loping. Last weekend my father and I replaced the waterpump and radiator on the car. When we finished, it began loping while in Park. It has also started stalling when changing from D to R.

At first we thought it had to do with the idle, since that is supposed to automatically adjust (according to Chilton). But it has been a week, and has not adjusted yet. I've been reading the forum and noticed several people with the same problem menting the Idle Air Valve/Motor. Any advice an replacing this? My Chilton's is very broad.

Thanks in advance for the help!
Dawn

The PCV valve is directly in the center at the back. You will not be able to see it. You will need to just work by touch. When you finished with the water pump/radiator did you forget any vacuum lines?

Thanks.
As for the vacuum lines, I am pretty confident that we connected everything that we had disconnected.