Returned the bum O2 sensor that was sold to me, got a refund because they didn't have the correct one in stock (even though the store's web site said they did), went to a different store, bought the correct part, took it home, and installed it. (What an annoying waste of time.) Cleared the code and I haven't seen it since...

I also built a custom relay harness with anti-EMI measures for my low beam HIDs in order to eliminate audio noise that was being generated when the ballasts were engaged. Tested and the noise is now gone.

Next I did prep work for a similar custom harness with anti-EMI for my highs and fogs -- but these will use the last two relay slots in the sealed Bussman relay box I built during the winter (the low beams don't). I hope to complete those Monday.