Thanks for the clarification. I remember reading something about the resistor for checking the circuit continuity but have a growing amount of information to keep track of and waning motivation to search thoroughly. Whatever the case I found it odd that the DTC cleared itself almost immediately, and these are 3 year old AC Delco O.E. sensors.

Since the last couple revisions I've had a couple attempts that didn't start on the first try, most recently a hot re-start this afternoon. These were both instances where I cranked around 1400-1800 milliseconds and then let off because it was obviously not going to run without intervention (I did not try opening the throttle). It felt like it hit on a few cylinders and then flooded (or possibly underfueled). Second, relatively long crank started and felt pretty normal once running. I'm going to try catching a log of one of these in hopes of finding the cause.