97 intrepid stalls PLEASE HELP!!!!!!!!

[nathaniel85]

ok guys i have a bad problem. i hope you can help. i ended up blowing up my last engine due to low oil leve, i know stupid right? anyway i just installed a used one. i am sure everything is connected but it stalls. sometimes it starts right up but others it takes it twice. then after going a bit and i stop it will stall. this only happens some times but it starts right back up. i ran a computer on it but nothing came up except my o2 sensor was a little slow but i now works fine, any i deas of what could be going on if so please e-mail me at [email protected] thank you i hope you can help.

also my check engin light is on

[AWP9521]

How do you know it is not a bad O2 sensor when the diagnostics picked up a problem and the check engine light is on? Especially if there may up to 4 of them on the car.