Reviewing the TunerPro RT logs, I noticed the MAT (Manifold Air Temp) was reporting >200F temps - that seemed too high. This sensor is in the air filter canister and is commonly referred to as the IAT - Intake Air Temp sensor. Found this chart to test it. The error in resistance seemed to line up with the high temps in the logs. Room temp, ~80 degrees, had 600-1200 ohms resistance which would place it too high in the temp chart. New sensor was ordered for ~$21.
I had trouble getting a decent reading with my free Harbor Freight multi meter so we'll see if it really is the sensor. It looked like an original. Could also be faulty wiring. That will take 2 people to test and a better meter...