Today, I noticed there's some vibration as it's revved in park -- especially when cold. Though it's possible a tune-up (or injector service) is necessary, it's not really a miss. I'm still thinking bearing(s). I confirmed this by kicking it out of gear on the hwy too. The effect directly corresponds to engine revs.

Because I'm also hearing a bit extra noise at startup, I'm leaning toward an engine accessory bearing issue. It's [somewhat] reduced after warm-up.