Since the search function brings up about 10000 pages when I seach CEL and Anti-fouler.

My local kragen has 2 sizes...which one do I need?

 

18mm is the size you need. You need two of those, one of them drilled out to 1/2" diameter, the other left as-is. Screw the as-is nonfouler into the s-pipe of your exhaust, screw the drilled out nonfouler into that one, and then finally screw the O2 sensor into that. Make sure you unclip the O2 sensor completely or you might damage the wiring from the tension of screwing it into the non-fouler. Once you've screwed it in, reconnect the O2 sensor into its clip and you're good to go.

Reset your ECU by pulling the negative battery terminal for a couple minutes. Go do the dishes, walk the dog, or whatever else you need to do. Come back, reconnect the battery terminal, start the car up again and let it idle for 10-15 minutes. You're all set!