Problem starting the car, 2000 non turbo jetta

This is my first time on this website, i just wanted to see if any other jetta owners have had this problem before. I have a 2000 jetta, the check engine light has been on for a couple days, the code is a bad cat/02 sensor. Now whenever i start the car and this hapens everytime it turns over for a good 10-20 seconds and then slowly putters and starts. Right after the start it pumps alot of smoke out the tailpipe, the smoke is gas, extra gas burning. It seems as though its flooding the engine with gas and then when it starts it burns all of it quickly. After the car is running it runs and drives perfect. Anyone know what this could be? Thanks