Alright, its the O2 sensor. I flipped them from side to side and the codes changed to P0161 and P2272. The sensor has probably been dead for a while but I wouldn't have known it since I've been running an after-market tune for years.

Ordered up a new motorcraft sensor and will solder it up when it arrives.

 

Just to update. I installed a $40 DY1038 Motorcraft O2 sensor and the problem was immediately fixed. Passed the emissions test yesterday with no problems.

 

Great news. Brenspeed is pretty good with their emissions tunes. Those were the same codes (stuck lean/heater circuit malfunction) my truck was throwing when an O2 was bad so I knew one of them had to be the problem. Glad you got it working.