Just an update. The underlying cause of the trouble was a bad valve cover gasket. Turns out it was coincidence that it all started happening right after I filled it with gas. The oil was everywhere! Anyway, I ended up replacing the plugs, wires, and coil packs, and pcv valve (mainly because of the hassle of getting at all that stuff), when I replaced the gasket. I cleaned up the plugs of the O2 sensors but I am still getting a check engine light from the bank 1 sensor 2. The code is "Low voltage to O2 sensor bank 1 sensor 2.

Do you think I might just need to replace the O2?

They are so expensive. There are some on ebay for $20 that you splice you own connector on to, but I am a huge advocate of "YOU GET WHAT YOU PAY FOR".

Has anyone had any luck with the cheapies?