[fiveohpatrol]

It's basically a vent to let out the air pressure in the crankcase.

It is on the very back in the center of the lower intake manifold (kinda hard to reach). It has a fairly large vacuum line coming off of it and that leads to the drivers side of the upper intake.

Yes you should replace it. It's an important piece of your normal tuneup. Don't get a autozone or other parts store PCV valve because they dont fit right and sometimes can cause a little oil to come out. Get one from a local ford dealer's parts dept. They're not expensive. But they can be hard to find/reach if you've never seen exactly where its at before.

Hope this helps