Hi all, Its been a while since i needed some info but alas the time has come again. After getting my 01 S3 tested for emmissions it appears that the CO level at idle is 0.8%. The maximum test pass is 0.5%. I have no fault lights on and the car drives great but this is a major problem if I cant get it through the test. I'm using octane boost and I'm wondering if this is causing a rich mixture?! Has anyone any ideas of how to reduce the CO levels even for long enough to pass the test. Your help is very much needed.