95 beretta z26 sputter

I have a 95 beretta z26 that we just recently bought so I or the guy we bought it from have limited knowledge of this car. It had a little rough idle and would sputter and put out black smoke on acceleration, the engine light was on after it ran for a short while, it said the map sensor needed replaced, so, I have replaced the map and o2 sensors, the iac was replaced before we bought it, since the o2 replacement it has improved with the idle, and the acceleration while parked has still a (miss) and blows black/tan smoke with moderate peddle pressure at about 3-4000 rpms. So here I am wanting to pick some brains since I obviously have none left...lol Thanks in advance for any help, Dave

have you tried a tune up on it

Thanks for the reply...yes, a tune-up was performed on it before we bought it. But, after driving it for awhile the car has seemed to stop the sputter and run fine. Guess I'm a forever skeptic... hmmmmmm