o2 sensor prob

[98talonNT]

Got the usual cel about the o2 sensor being bad. It goes on and off a lot, so do you think its time to replace it?? Also, how can i tell which one is bad. I know there are two sensors, pre and after cat, dont want to have to replace them both if i dont have to. Just in case you need to know, this is for a 2gnt. THanks guys,
-98talonnt

 

[siueclipse]

go to autozone and ask them to scan the car. that will tell you.