04 Freestar O2 Sensors, Misfire Fix

I replaced the O2 sensors in my 2004 Ford Freestar SES minivan (3.9L V6). I had given it a tuneup (new coil pack, spark plugs, plug wires, fuel and air filters) about 800 miles prior to this and began having a misfire and bank 1 lean codes.

The codes I was getting were
P0316 (misfire in 1st 1000 revolutions)
P0303 (misfire cylinder 3)
P0171 (bank 1 stuck lean)
P2195 (also a bank 1 lean code)

I had seen a couple of videos where mechanics had been worried about the "PSHT" sound upon rapid acceleration being related to clogged catalytic converters. While I had the O2 sensor out of the cat, I looked in there, and the honeycomb is indeed burned up, but the general consensus from the vacuum readings I obtained was that I don't have exhaust backpressure issues.

I hoped replacing these would help the misfire, but had little hope it would, and it indeed did help, but it made the lean codes go away. I had to continue to drive it with a misfire for most of the week due to work obligations, but was able to finally get to Autozone, where I attached a spark checker to cylinder 3, which appeared to flash appropriately so I replaced the spark plug. That didn't help the misfire, so I replaced the new coil pack with another new one under warranty. This fixed the issue and it now drives with no codes. Not bad for a vehicle with 257k miles on it. Yes, my Low Tire Pressure light is on, I addressed it.