O2 Sensor Extenders

[bigsapper]

Hi, I'm posting here because you guys are the tuners. (Admins/Mods, if this is inappropriate, please move accordingly)

I have a 2014 Silverado 5.3L. I've got Kooks headers & green catted y-pipe but it still throws P0420/P0430 codes with the stock tune.

What are your thoughts on running one of these?
http://mpcart.commercev3.com/images/jhook_defouler2.jpg

I've read that it works to prevent the cat inefficiency codes, but I've also read that (different make/model vehicle) newer vehicles now use the rear O2 sensor for fueling, and therefore using the extenders screws up the ability to tune or run right.

Thanks in advance for your advice.

[joecar]

If that's the rear NBO2 then it will not see the actual lambda pulse when the P0420/P0430 test runs... so, yes it may pass the cat efficiency test, but it may fail the activity test for the rear NBO2.

Not just the newer ECM's, but even some of the older ones may use the rear NBO2 for fueling if they detect any inability to trim from the front NBO2, but it would be an exceptional case where this would happen, it does not normally happen.

[bigsapper]

So my cunundrum is that I want my truck tuned, but I also want the ability to run a completely stock tune with the headers, without it throwing codes.

[ScarabEpic22]

Easiest way would be to tune it, but I know some people use these "J-bungs" to trick the rear NBO2. May or may not work, and they're cheap.

[bigsapper]

Primarily I am wondering if the E92 uses the rear O2 for fueling.