I got the code 43 yesterday for the knock sensor. I was prepared to fix that, but my engine started misfiring today. I have no idea what it is. It started misfiring after I did a 180. I parked it before I went to work (3:30pm), and I just got off at 10:30. I cranked it up and it ran fine for the first few minutes. After three or four minutes it started doing it again. Coincidentally, it started misfiring again after I slammed the gas. I didn't get an o2 sensor code, by the way.