Update:
Last night, I started the truck up, and let it idle. After about 3-4 minutes, I started playing with the defroster. It's definitely not that.
After that (defroster off now), I started revving it up alittle at a time, trying to catch a pattern. As soon as you start revving, you can hear a lite ticking. At 1500 rpm's, its like something happens, and the thing just start ticking like crazy. It's like its almost glued on 1500 rpm's. To me, its surprisingly loud. Not something I feel is normal at all.

Took the truck for a ride through town, down the highway, and back through town again. Probably a 20 mile ride. Everything was nice a warmed up to normal opearting temperature. Outside temperature was about 25 degrees or so. Got back in the driveway, put it in park, and performed the same test. At 1500 rpm's, it is an un-mistakable noise. Anybody would hear this. It seems to just get faster as you rev it past 1500, but it gets to the point where the engine/exhaust it louder than the tick.

To me, I'm sure its not the defroster. I'm about 98% sure its not the injectors. It is valve train related, without questions. There is some solenoid that clicks when its warming up or something, but this noise is mechanical.

The only thing I'm wondering is this engine has Variable Cam Timing, correct? If this is the case, it has oil control solenoids to perform this magical stunt of advancing or retarding the cam based on the PCM's wants/needs. This may be the culprit, and would make sense why you could really peg it at a certain RPM, but I may be off track here. Not sure.

If anybody reads this, and could possibly find the time, I would really appreciate it if you could just try this with the truck warmed up. In PARK, rev it up alittle and at 1500 or so, see if you can hear anything. I know a mechanic at Ford, and I am due to be at Ford monday with the wifes car for service. Hopefully he can shed some light on this.............