The 02 sensor monitors your exhaust and helps the engine maintain the right air fuel mixture. However, if it is way off it will cause seeking as yor engine is constantly trying to overcorrect....The best way to set the mixture is to have an exhaust analyzer but they are very expensive. The next best way is with a dwell meter...instructiuons are in the manual and in archives under the term dwell meter procedure...you want the needle to flucuate around the 45-50 pecent range with a 10 percent swing.... mike c 2109