sooo, been riding around in my new-to-me 25k mile '01S for a year.  decide to change oil.  My thanks?  My first cel.  Ordered a durametric and retrieved P0133, P1275 (aging precat O2 sensor bank 1-3).   Gathered some realtime data, expecting "Aha! moment".  Got wtf moment.   A door leads to another door.  In case the pic doesn't work:
0 - 15 sec : all 4 sensors read 0.45 volt
15 - 42 sec: precats goto 0
50 - 1:30 sec: post cats goto 0
1:37 : precats begin to ocillate 0.05 to 0.8 volt @ 4 sec interval
1:40 : postcats squiggle around 0.75 volt