Engine Light - codes PO420 and PO430

Hi
2008 double cab with a 4.7 and 176,000 miles. Truck starts great, runs great and is smoother than any other V8 I’ve owned. However.....it throws these codes.....only these codes at the same time.
PO420 below threshold bank 1
PO430 below threshold bank 2
I can clear them with my code reader.....but they reappear after 50-70 or more miles. Totally random. What do these codes mean? How and where can I start troubleshooting this?
Truck still runs great.....will the light on affect anything??

 

Whatever you do, don't freak out and buy new cats or anything like that.

Also don't freak out and start throwing 02 sensors at the truck.

Go to your local autoparts store and buy a can of MAF sensor cleaner. Pull the negative cable off your battery, remove the MAF sensor, then clean it.
https://www.youtube.com/watch?v=xQGSkWEC_u4

Because you have both P0420 and P0403, this points very strongly at the MAF sensor. If you have a scanner that leads live data, you can drive around and monitor what the MAF is doing to see if it makes sense (reading more air the higher the RPMs are, dropping back down as expected, and showing approximately the correct value at idle).

 

Thanks
I’ll try this tomorrow
I was also reading up on the spark plug foulers mounted in the o2 sensors

 

The non foulers will likely be more annoying than just fixing whatever is triggering the problem. If you just had a P0420 and nothing else, and maybe you had a Nissan, I'd say go for it on the non foulers!

 

Following to see if this works. I am having the same issues.

 

My vote is dirty MAF or bad cats. May want to check out this thread... he ended up with new cats which IMO was his original issue for the 0430 and 0420 codes.https://www.tundras.com/threads/201...ill-not-reset-with-tool-after-replaced.80755/

 

Any chance you have long-tube headers?