I checked the PCV valve the other day and it appeared fully functional, and the vacuum lines like practically everything in the engine compartment are brand new. I even sprayed the cruise control and evap cannister lines with starter fluid to ensure that they weren't leaking either, no dice.

As far as the sensor is concerned I guess I'll order an and see if that does anything. However, I'm going on a road trip for Thanksgiving and likely won't be able to work on the truck for the next couple of weeks. I will post an update once it arrives and is installed.

 

Update: I received the sensor, installed it, reset the PCM, drove the truck ~50 miles and bam, no code! It just passed CA smog this morning and is now registered. Thank you all for your help!