My car's all fixed up. This was the culprit... small crack where the header meets the flange on the passenger side. Better view of said crack...
So I did some other shit, then I cleaned up the area well with wire brushes and such... then my best boy/roommate Joey welded 'er up. I cleared the code immediately after. No CEL as of yet but I only drove a couple miles. If it's gonna come back it will do so on my way to or from work tomorrow, so we'll see. If it does I definitely need that stupid censor. But keeping my fingers crossed that it won't.