Thanks guys! I checked the PCV hose in the link Rockledge put up. I was feeling that elbow at the back of the engine, and I felt something.
I figured it was a mold line, as it didn't feel like a hole- but I figured I'd best get a good look at it, because it was such a common problem.

So while I was trying to figure out how to take it off, this is what I found....


Looking a bit closer...


So it was the other end of the same hose that's been giving everyone else trouble.

I screwed around for a couple minutes trying to take it off cleanly, but decided I'd be best off just cutting it off along the existing failure. That didn't take too much time.

I went to the local Ford Dealership and picked up this:


It's the entire assembly from the back of the engine to the air intake in front. Total cost: $37.
In the other thread, one guy paid $6 for the elbow, and another guy got the hose for free.
I was running out of sunlight, and you guys showed me the OTHER elbow in that run failing, so I just paid it.

I went home and installed it pretty quickly.

I got home from work around 4pm, surfed the internet for a bit, went out, found and cut off the failed hose, went to the dealership, got back and installed the new run by 5:20 pm.

If you just cut off the old hose it's an incredibly simple task. Just don't lose the spacer clip back by the fire wall (two more on the passenger side of this hose/tube run.)

Anyway, I hooked up the scope program, and the difference was immediately obvious. Before when I was idling, all the O2 sensors would be at the bottom of the scale, and only go into the normal variance when I was under way.

This time, the O2 sensors immediately displayed normal-ranged variance. I drove the truck for 20 miles and didn't get any trouble codes, or even possible codes. Also, a sucking sound I heard before- which I thought might have been normal throttling noise across the air intake valve- was gone. (I would have mentioned it, but I noticed it after my initial post.)

Idling was perfect.

The trip wasn't enough for the emissions screening to complete, but it displayed 'Not Ready' as an overall score, not 'Failed'. The catalyst, EGR, and some other thing are still 'not ready.'

With no DTCs or possible DTC's in, I'm gonna hope these just wash in over the next couple dozen miles.

Thanks again guys!