I just noticed a few days ago that a very light white smoke is comming out of my exhaust. Not alot of smoke and not all the time. It didnt happen until recently when i intalled a test pipe. I was thinking that it could be possible that with the test pipe my car isnt getting a correct readign and causing it to run to rich/lean and hasnt adjusted itself yet. Anyone have any suggestions on why it would be doing this or what i can do to fix it.

 

the first o2 sensor will set air fuel for the motor, which is before the cat, so there is no problem there, its when the second o2 sensor reads that the cat is not working because of unfiltered exhaust, that a code is thrown, and most of it is moisture anyways, make this place a bit greener and put the cat back on.