i agree w/ the above post. But for the time being, have autozone clear the code, see if it comes back. If it does then you have two options. 1 being the post cat oxygen sensor (easy fix) or being the cat itself for that bank. U would need to be able to look at live data to be able to tell which one is to blame. If that is not an option then u will have to guess, i would start w/ the cheeper of the two being replacing the o2 sensor then clearing the mil. gl w/ fix