Car is flooding itself

I have a 1992 Grand Prix 3.1 L with 132,000 miles. When starting it, it kills, I always get it started again but have to stay on the gas to keep it going and need to floor it to be able to go with out it stalling. Seemes as though it's missing but have been told it's flooding itself. I've replaced the o2 sensor and the computer and they checked the fuel pressure which is fine. You can smell gas bad and is blowing some smoke from it. I've been told numerous things it could be but don't have the funds to go down a check list of possibilities. What could cause this? Where should I start first?