This is crazy ,but I have the exact same problem! I had same code P0133 and ran the car with CEL for few days, car ran fine and put it away for few days. After long weekend, Started the car and it didn't run with all 8 cylinder. I came back next day and this time, car didn't start at all, just cranks.
I thought I had some other problem ,but ran into your post about your problem. I've already ordered pre- cat O2 sensors... let you know what happens this weekend.