P0420/P0430 Codes After Cam Gears

Hey all!
I recently Had a shop that seems reasonably competent install exhaust cam gears in my 06' 4.0L. It's been about 2mo of driving since the install and I now have P0420/P0430 Trouble codes that reappear after clearing with my scanner. I know there are multiple factors that could cause this code, but I know one of them is timing, and since the cam gears change exhaust timing I was curious if you think that'd be it. The 02 sensors seem to be giving reasonable data.

The truck is running fine, albeit it feels a bit slower since the install. I have not yet had it tuned. Any ideas what might be causing the codes/how I can confirm without taking the valve covers off, that my timing is correct.

 

How soon after the cam gear install did the codes appear?

Speaking to the cam gears, my impression was the truck was noticeably peppier in the low RPM's. Like, there was more yank when I accelerated and could break my tires loose compared to prior. This is without the tune and I still run without a tune.

 

Most likely the converters if you have no exhaust leaks.

Will your scanner graph the upstream and downstream AFR & O2 sensor voltages?

 

Yes, it can! What values should I be expecting?

 

Happened about 1000 miles of driving afterwards. the 20 & 30 codes happened at the exact same time which is why i find the cats both dying at the same time suspicious

 

With the truck warmed up driving or idling you should see you upstream sensors switching between around 3.2 -3.3v and the downstream sensors should be pretty steady around 0.6 to 0.8v if the converters are functioning properly.

 

So, after driving around all day with the OBD tool hooked up, I have generally steady .72v on the downstream sensors while on the gas. It drops a bit when i let off but i assume thats normal. I'm stumped