Maybe a month or so ago I came on the forum and found out that my O2 sensor wasn't working. After buying the new one (once I got enough money) I check to make sure it's the right electrical connector, and as I'm doing that I just happen to notice that one of the pins had built up that same kind of corosion that the battery terminals get. I scrape off as much as I can with my keys, plug it back in, clear the codes and 300 miles later im still CEL free. Moral of the story always make sure it's got a good connection before you go out and buy some $75 part.
