In December, before parking my car till yesterday, I had noticed a very little bit of oil consumption. And then I came down on a misfire in cylinder 4. The day before I left it, I saw the spark plug boot was not seated all the way, and began a sigh of relief when removing it to reinstall it. That sigh of relief vanished as soon as oil came out with the boot, only to find the entire spark plug tube was filled to the top with oil. My spark plug was torqued appropriately. Right then and there, I removed my plug and inspected it. It was oil coated, but otherwise fine. I wiped it, reinstalled, and kicked this problem to the future for when I could pay more attention to it.
During the last couple months I thought the spark plug tube might have had a knick in it, and it possibly wore through the spark plug tube gasket. Today, I removed the driver side valve cover in order to replace that gasket, but upon inspection I learned there is a metal collar that wouldn't have been affected my the minuscule knick that I did find. Replaced the seal and buttoned the car back up. Guess we'll see what happens.