i recently bought my msp, apparently it's had 5 previous owners and has had some minor work done to it. i happened to look under my car and i noticed the second O2 sensor is placed BEFORE the caty. my check engine light is coming on because of my second sensor. is there a reason that the o2 sensor is where it is, or is the person who did the exhaust on my car an idiot? The reason i'm asking is because my car seems to have an acceleration issue like i'm burning too rich and its driving me crazy.