p431 code and running like crap

[Macinudo]

After years of ignoring the light, I think it may have gotten me. The only code I have is the p431 code (Cat efficiency below threshold, bank 2). Now my question is is do I need to change the cats, or could I just do the O2 sensors. I have had this have code for at least 4 years, but until recently the vehicle has run great.

 

[gavin]

sounds like the code is coming from a downstream O2 sensor.

while it certainly is possible it's an O2, it could be that the cat has crapped out and will need replaced.

it wouldn't hurt to try replacing the O2, but remember that it may not fix the issue.

although, if it were an O2 sensor, the running like crap probably would have began when the code first appeared.

 

[aldive]

I wouldn't replace anything until I did more diagnostics.

Good luck ....

 

[Macinudo]

It runs the worst when cold, and gets progesively better once it comes up to temp, but still not well. Sort of feels like I'm dragging an anchor. My main question about replacing the O2 sensor is, if the sensor was bad, wouldn't it give its own code?

 

[aldive]

Hook up a scanner to the O2 sensor(s) and check their function.

Good luck ....

 

[Cobraguy]

downstream O2 sensor does nothing for drivability. It only tells you whether or not the cats are working. You can also get the code if the sensor has served it's life and is worn out. It's up to you to decide which reason.