backfiring throw carb on 1995 Buick Roadmaster

i bought a 1995 buick roadmaster for a hundred dollers.The guy i bought it from replaced the moter and now backfires thro the carb when the moter is cold and the check engine light is on the code comes up as a o2 sencor not to worried about that. If you sit with it in drive the check engine light goes off untill you give it gas. can anyone help me ive giving up on the thing thank you and god bless

by in Freeport, IL on January 10, 2011
1 answer
ANSWER by on January 10, 2011
FIRST THERE IS NO "CARB". YOU MEAN INTAKE. WHAT ARE THE CODE NUMBERS.