I'm back again. The disappearing CEL was only temporary and it seems the gas cap "fix" was coincidental.
After a steady week of the CEL light on, I had the code read by PepBoys for $21 and it came back to the O2 sensor (specifically PO130 O2 sensor bank# sensor#1) The dealer tells me this is the one forward of the catalytic converter.
Anyone have experience changing this sensor or have some pictures to share? I have moderate mechanical skills but no way to get the vehicle over my head, if that's required. I read the pdf on this site but the picutres don't seem to match my vehicle and didn't seem to apply to my model?
Any help is, of course, appreciated!
Link to orig thread