Thanks for the reply.
My first thoughts: Ugh, another sensor? ... Well anyways, what's this sensor called? I haven't looked under the hood yet to see which one you are talking about.
However, I did notice today when driving around the same amount as usual that the problem has gotten a LITTLE better. For the first time in many months I saw the dash engine temp gauge go to 1/4th heat and the oil temp gauge move enough so that it was no longer at bare minimum. It's a start! And I think it made the engine run a tiny bit less rich too, if I'm not imagining things.