I got my CEL scanned today at auto zone and the guy said it was my 02 sensor after the cat. How much do these run price wise and is it a labor intensive job to change one? Is this a common issue? Also, my engine is bone stock, 104k miles, if that matters, thanks.

 

it could be a bad cat causing the cell

 

Wats the code??
P0420 is cat low efficiency or something like that

 

if its actually the 02 sensor it costs around 60 bucks and is an easy fix. get under the car near the cat, find the old one, unplug it, use an 18mm or something to get it out of the exhaust pipe, and reverse to get the new one in

 

This and get some WD40 to spray around it to get it to break loose I used a wrench, and a hammer to get it break loose once spread with WD40. Its super easy to get to like he said.

 

Ok, thanks riceburner

 

Use something stronger than WD40. Like PB Blaster/Liquid Wrench.