Hi, i'm hoping somebody can help me with this problem with my 307. At idle the revs are jumping between 800 and 1200 rpm. Last week i replaced the oxygen sensor because the anti pollution fault warning was on. I've had a diagnostic scan done and it came up as camshaft sensor over advanced/retarded....does it need a new sensor and can i fit it myself! Hope some of you guys can help me out, thanks a lot, paul.