One more thought; when you installed the new sensors, how much did you torque them? If you really leaned on them, perhaps that contributed to the shorting failures of both? Unlikely, but we look for the simple things first.
Don't remember the torque, but it's 30 lb-ft for Toyotas.

Oh, in all my years of messing with cars, I finally saw my first CEL due to a faulty O2 sensor, just this weekend. I know it's common, but I guess I've been lucky. My wife's sister has an '01 Camry, and it threw the code Saturday. Sure enough, O2 grounds shorted. It cost $180 at the local parts store!!!

Go ahead and fix that rear main leak, it only costs $20 (and pulling the tranny)! Oh, are you sure it's the rear main? The 103 is infamous for leaking valve cover gaskets that run down and drip of the rear main area - fooled me the first time.

DG