1985 Dodge Diplomat Runs bad

My car runs alright for a little while then it starts cutting out, popping through the carberator almost dieing on me. If you hold it to the floor it will cut out and has no power then you let off the gas it cuts out then it like picks up speed. Sometimes it will not start after it has run for a little while, it acts like it is flooded. When you first start the car up I'll have black soot on the ground.I told my husband to change the carberator, but he's not for sure if that will fix it. During the summer when you went around corners it would almost die if you didn't give it gas, sometimes it would anyway. Its just gotten worse this winter. HELP!Thanks