I bought my 08 gt a yr ago from a dealer. After a week of owning it the check engine light came on so I got it checked. All codes led to the o2 sensors. Now that inspection is up I can't pass. My mechanic has tried multiple times to turn the light off but it only stays off for 100 miles or so. I have a bbk long tube header and bbk xpipe set up with two cats before the xpipe. My mechanic says that I could try to get two more cats set up down stream and rerun the o2 sensors but he's not 100% sure if that will work and if it Dosnt it will be a costly worthless install. Dose anyone else have a prob like this?