O2 Sensor

I just replaced the O2 sensor on my 1989 300E. When I fired it up it ran great however when I floored the throttle some white smoke came out of the exhaust and the engine started to miss violently as though something was cutting out at high rpm's. Does changing the O2 sensor reset the mixture the engine senses? Before changing out the O2 sensor I noticed black smoke comming out the exhaust at high rpm's but no violent shaking. Mixture too lean know or what? Thanks for any comments!