I've checked for vacuum leaks, spraying all the usual suspects with starting fluid with no difference. I've changed spark plugs (Bosch 9605), new injectors (Standard FJ463), new Motorcraft coil packs, and new spark plug wires. PCV valve is still good (rattle test) and the hose going from it to the plenum is new. I replaced the plenum gasket while I was in there.
Misfire on cylinder 5 and bank 2 lean codes are what instigated this. They are both gone, but now I'm getting a misfire in 2. Shakes a bit on startup, kicks up as soon as I put it in gear. It's worst when I'm stopped, and will jerk more at lower speeds then higher speeds, more when I'm cruising then accelerating.
I'm at a loss as to what's going on. I'm suspecting fuel pressure regulator in the tank (gas gauge is already a bit wonky, especially under half a tank), cylinder 2 fuel injector is bad out of the box or the o-ring where it meets the head is creating a bad seal, or there's a sensor that's going bad.

 

If you have 100K miles or more on your Oxygen sensors I suggest you replace them. Bosch is the original manufacturer for the O2 sensors, or use Motorcraft, don't put cheap aftermarket ones.

 

Yeah, I ended up figuring it out. One of the new spark plugs I got was bad. Drove over to O'Reilly's to rent a compression tester and test in their parking lot, everything was testing ~80 (Haynes says 100+ so long as everything is within 15 of each other). Unless I was using it wrong or the test was faulty, I was thinking I needed to get a leak down tester. Had dropped the spark plug for the offending cylinder as for some reason it was the only one my magnetic spark plug socket wasn't magnetizing to. Put it back in, went to plug in the spark plug and the ceramic end was laying by the mirror mount. Grabbed an Autolite single iridium to get back home and ordered a replacement Bosch double iridium to get the next day. Got home and back without it acting up. Swapped in the replacement Bosch the next day, drove around for ~30 min with live data going on my OBD2 and got 0 misfires. I sure as hell wasn't happy about a DOA part, but it ain't worth crying over spilled milk.

 

Good work. Thanks for sharing.