98 explorer

Sounds like either a sticking IAC valve or the infamous intake gasket leak. When checking for an intake leak, the testing must be performed when the problem is occurring. We see techs (that should know better) trying to find such a vacuum leak on warmed up engines... since thermal expansion has helped seal the leak, you can imagine the outcome...).

For your fuel filter... dirt and small pebbles can find their way into the fuel line connection. This stuff will keep the tool from expanding the retainer spring far enough to release it. Tapping lightly with a screwdriver handle os such can help dislodge most of it. Also, rotate the line on the filter to help break the O-rings loose and, if necessary, a wee snort of penetrant (on the joint...) can help.

I spend 90% of my time working on diesels so I can't help with PCV location... at least not by "foggy, old man memory".

The PVC is on the back on the engine (firewall side). Almost impossible to get at...

Why couldn't Ford put the PVC valves on the valve covers where they normaly are (were) found? I've got a 5L V8 and I ended up putting a nylon tie wrap around the PVC hose letting the loose end stick up where I can see it. I follow the tie wrap to the PVC hose, find the PVC valve and pull the PVC valve from the grommet and remove the PVC valve from the hose. I've found that this is much easier than fishing around hoping to pull on the correct hose.