My ISP has deleted the entire message database, so I cannot follow-up to my original post.
I will thus make this new posting a follow-up to my earlier request for guidance/help.
Summary: Check Engine light on, Dealer pulled codes for Rear O2 sensor, Knock Sensor and Catalytic converter.
Today I got a new Bosch OEM O2 Sensor from PartSource for $153.00 including taxes and a small shop around the corner installed it for $20.00 cash and then reset the codes. I have a rather long trip planned for Wednesday, so we'll see if that has fixed everything, I'll have the dealer pull the codes again, at least to see if the Knock Sensor is happy.
I had two tires with slow leaks fixed also, a screw in one and a nail in the other.