It was the O2 sensor. The O2 sensor on one bank was replaced last week. The other bank's O2 sensor failed and apparently caused the problem. I didn't know that the O2 sensor could lead to such degradation. Good news I guess, relatively cheap fix other than the tow.
If you have full coverage, I would call your insurance agent. Most all policies have verbiage written deep down where it's hard to find that they pay for tows. My father in law used to drive a tow-truck and said nobody ever knew this but they all thanked him later after he told them to call.