5.3 Check engine light??

Yeah I changed both of my O2's and cleared the code as welland everything is running good! (knock on wood) I hope that resolved my problem as well.

Well its me again and my engine light is back on tonight, 0420 i think it was something about catalist threshold bank 1????something like that, im not sure but does this mean that i FUDGED my converter????? I cleared the code but im sure its gonna come back on....

Anybody know what this code means??

Google is your friend.

Troubleshooting P0420 Catalyst Code

Thats some good info Thanks Madd Maxx, im wondering if maybe this happened cause i only replaced 1 O2 sensor, and not both????

I would just replace both of them. You could have a clogged cat now also...

I have also found out that mine keeps coming do to the fact that I have a higher stall converter now and the tollerences need to be changed in the tune some.

jes i hope the cat isn't clogged I just got a new truck yesterday and i just want to sell this truck, how would i tell if the cat is clogged would it be hotter that the other one????

Throw a spark plug non-fouler or two on that O2 sensor if you want the 420 code gone. Did it on my 4.8 and it worked like a charm.

well i cleared the code a few times with my superchips flashpac, but it keeps coming on, what is a "spark plug non-fouler or two on that O2 sensor"???