5.7 hemi idle and backfire

So I'm guessing with the O2s went off-line, the ECU commanded a limp-in mode, went rich, and sooted up the plugs.Does that sound reasonable? Or do you suppose the engine was rich to start with and sooted up the O2s first.
The reason I wonder is; how long before it happens again?
Should the fueling be changed, or should the limp-in program be changed?
Or was it a fluke, never to be seen again.....