If you are 10:1 then you need to tune. That could cause your engine to choke.

ok, so running on two cylinders is probably why you are seeing rich values. Have you been able to confirm which cylinders it is not getting spark on? while idling pull one plug wire at a time and see which ones make a difference? What are your ignition settings?

Well now my car won't even start. It had spark on all plugs. I'm getting fed up with this thing. I have no idea why it won't start now.

how did you test spark? I have seen some funky stuff on that before where bad plugs would cause a misfire but spark test with no plugs was fine. i ended up clipping the timing light to it and seeing which ones were sending spark while connected to plugs.

I don't think so. The o2 sensor is measuring uncombusted oxygen in the exhaust. A misfire means there is a bunch of extra oxygen which will show a lean AFR.