Ok, like a lot of others I believe my cats are clogged and ready to do something about it. My questions are, exactly how many cats does my 06 5.4 have? And how many and which ones have o2 sensors? And how many resonators do I have? I'm looking at trying to eliminate the resonators and any of the cats that do not have an o2 and replace the cats with o2's with hi flo cats.

 

2 cats 4 o2 sensors 2 resonators

 

4 o2's? Wow, that's ridiculous. So I take it that each cat has 2 sensors each?

 

no, there is only 1 in each cat. Here is the part number you need:
Magnaflow 94136



installed them on mine last week and they solved the problem of the code being thrown as well as gave a little more voice to the exhaust

 

If you crawl underneath your truck and look, all of your questions will be answered.

 

Yeah it looks like that's what I'm going to have to do, it never amazes me how many different answers you get on here when the question you ask should only be 1 answer. I mean I totally understand that our trucks vary year to year and model by model but when you ask a specific question for a specific year and model, then realistically there should only be 1 answer

 

Ducky gave your the answer

 

After the minfolds on each side is a O2 sensors then the cats then another O2 sensors then the resonators. So each side as 1 cat and 1 resonator and 2 O2 sensors(one before and onw after the cats).

 

What's your year, engine, 2wd or 4wd, and did you eliminate the resonators?

 

So, which O2 sensors matter the most? The one's before or the one's after the cats? Or should all be replaced at the same time?