0.02 - Duralast products tend to be either BWD or SMP (Standard Motor Products). Same manufactures that are sold at Advance and make a lot of the reg Napa parts. BWD tend to be the manufacture of Napa Premium parts.
I had a similar issue myself a bit back. Ended up being my coil pack shorting out to the distributor housing. So, pull your cap, then the cover for the distributor. Check for any "electrical" dust. Black soot where stuff can be shorting out.
Plus pull the coil back and check the bottom of it. Thats where mine wore and started shorting.
As for replacements, at the parts store. You can only get reman distributors with all new parts. They run about ~300-320. Plus you turn in your old to not pay a $20 core.
You can find the coil pack and ignition module separately around on the web though. Prices, I dont really know.
I never threw codes either.
As for you current code for the Bank 2 Sensor 2. Check out TSB NTB99-004b. Talks about that and a grounding issue causing it.