General Maintenance & Repairs - replaced opti but car runs rough time to time

i recently had my opti replaced along with new plugs and wires. From time to time when i come to a stop it starts idling rough, and when im accelerating or just driving it bogs and seems to be lacking power. also some black smoke when coming down after reving it up. Other times it runs awesome i can feel all the power through out the rpms. i need to replace an o2 sensor would this make it run rough? Could this be my fuel filter? Anything else that could make this happen?

How Many miles? Id say fuel pump. Search the LT1 Forum here for more information

i have a 2000 ss and i have the same problem my rpms used to be at 750 and idle soo smooth i changed plugs and wires it now idles at 820 or 800 but its rough i bought the tr55s and msd wires off ws6 store and i didnt gap the plugs ... i also was thinking could it be the o2's?????? someone chime in please