I have an 04 5.4 3v I got a p0430 code come up and have to pull the 02 sensor to put in my back pressure gauge to determine if my cat is plugged, with the torque app I can see that the secondary 02 sensor voltage fluctuates as much as the upstream on bank 2 however on bank one the secondary one stays pretty much stable which leads me to believe that it has taken a crap on me. I can turn off my secondary 02 sensors with my sct programmer so I have been thinking of just cutting them out and adding in a single 2.5" high flow cat so that I remain emissions legal and once that is done then possibly installing a flow master 50 series muffler. So my question is has anyone done this in the past gone from dual to single cat and what was the result sound wise as I do not want my truck to be loud.

 

If your asking if you can delete the rear cats then yes you can.. I did it with no issues.. Check my profile for a thread I started called dual exhaust tip placement and style for pics and vids.

 

I'll start with officially saying that I don't know. I'm sure that technically it could be done. However, I don't think it's a good idea, and here's why. If you want to stay emissions legal, you're going to need o2 sensors. If you're going to have them anyway, I don't see the point in combining both banks to the same sensors. You'll miss out on information that can greatly help to diagnose any problems the motor may have in the future. Plus, you would have to get a specific tune for the computer to recognize a single set of O2's to maintain the legal status, if that's even possible. Now if you decided that you don't care about it being legal, then just cut the cat's out and delete the O2's.
Basically I think it's a neat idea, but not feasible.