I was chasing a temporary idle surge by cleaning the MAF sensor and replacing the pcv valve. The former is original, the latter, probably so. Pulling the pcv valve caused the 90* elbow hose to break in half and looks like it was split for some time, too. I guess that explains all black oil smudges my hands collected in a place they weren't expected.
Of course, it had to happen on a day when the local NAPA is closed. And another thing I discovered was that chipmunks (maybe squirrels) are using the air box as much as the filter is using it.
