4.8l cat codes

[Hdchevyclassic]

Need some opinions on what the heck is going on with my 2007 silverado classic. It has a 4.8 litre vortec with an afe cold air intake, edge cts2 programmer, gibson shorty headers, and a 3 inch catback exhuast. I have the code p0430 coming up but cant figure out what it is. Ive done a back pressure test on the cats, and did knock sensors and all O2 sensors a year ago. It doesnt feel like it has a misfire and im very mechanically inclined and everything in this truck is looked after. When i bought it there was a 4wd code and it wouldnt engage so i swapped out the button cluster in the cab and now it works fine. Other than that the truck has been perfect but id like to figure out what the heck is setting off the code. I have no exhuast leaks and the cats checked out perfect, anyone know what else it could be? Im looking for anything at this point, i hate check engine lights and have cleared it with the programmer but it comes back very shortly after being cleared. Thanks

[riverbanks]

You could try cataclean,sold at all parts stores,I have used it a got rid of 420 and 430 code,20$ worth a shot

[sefiroxx]

430 is bank 2 efficiency loss.

Usually, when a cat fails, it's due to some problem with the engine that is emitting too much of something - either due part failure (injector stuck open) or sensor failure (MAF, O2).

Cataclean might help, but only temporarily unless you fix the source problem. You'll need a scanner to see sensor outputs and to see if the computer is responding to the outputs

[bkeith5050]

You might have a exhuast leak.  The PO430 code came up on my truck when i installed a true dual system.  FOund out I had 3 exhaust leaks which was causing the downstream O2 sensor to not read correctly due to the lack of back pressure.