HELP!!!!! 1990 Mercury Cogar coughing and sputtering, wont run properly.

I have a 1990 Mercury Cougar 3.8L NA that I have been trying to get running properly, It has new water pump, head gaskets, alternator, and other misc and I just installed a new idle air control valve today and it still coughs, sputters and blows some black smoke out the exhaust. I dont know if it needs a tune up ( spark plugs, wires, cap, rotor, ect ) or what the hell is wrong I have to go to work at 12:00 today HELP!!!