Ford: 93 ford exl,porer, oxygen sensor, exl

Question
My truck v6 has been,  wanting to cut off .The RPM hand goes up and down. It feels like it accelerates itself when im on a redlight. I changed the IACV but nothing different. The check engine light comes on then off when im driving. Their is also black smoke out the exhaust when it acts up. It quits idling for a few minutes and black smoke quits, but then press the gas again and it does it again. This is my first truck ive owned so please give me anyadvise on this thank you.  Im also thinking its the EGR or the sensor. please help

Answer
if the check engine light is flashing have NAPA or Advance auto pull the codes for you, they will usually do it for a small fee if not for free. with out codes its hard to make an good solid diagnosis, especially over the Internet, but at a guess with the information provided, i would have to say Oxygen sensor, EGR. also check air and fuel filter, are you using good clean gas? did you use any questionable fuel just before it started acting up? check your spark plugs to see if there is heavy carbon build up, this can cause misfires and may be the reason for irregular RPM. most important to have the codes pulled first.