Converter

Rockauto for catalytic converter? If so which brand is OEM? Also, O2 sensors & MAF OEM from rock auto if possible.

 

Denso on 02. Hitachi on maf.

 

Bigger question is: Why are you replacing? Is it because of a specific code?

If it's because of theft, these trucks can be really picky about throwing codes on aftermarket units. So far, we only have confirmation on the forum of three confirmed no-code brands: Walker, Magnaflow, and the Summit Racing store brand. And OEM, of course.

I don't think anyone has tried Davico or others. Walker is probably the most-budget brand you can get.

But if your cats are still intact, and you're throwing a code about 'cat efficiency', and you have a V8, you really should try swapping your O2 sensors from passenger to driver side and see if the code moves with the sensors. If it does, you need to be replacing both sensors on the side that's now throwing a code.

 

Read this
https://www.tundras.com/threads/which-bank-is-which.123370/

 

Oh. You've already been there. Disregard

 

Thanks, replied there immediately after here and realized what's up. My point still stands:

• Use poor man's tactic to confirm it's not the O2
• If confirmed it's not the O2, replace cat with brand known not to throw codes.

I'm not going to put money on it b/c it's the internet, but I bet it's the O2s and not the cat.

 

I would go with a CARB compliant CAT if you don’t want to risk throwing codes.

 

Should I get downstream O2 sensor for both sides? Just making sure I get the right one between downstream and upstream.

 

Nope. Just the side throwing codes.

Best practice is to replace in pairs on a single bank any time there's a sign one is failing. Not just because the other one is potentially right behind it with failing, but because there's a few conditions where one going bad may actually throw codes suggesting the other is bad. And with cat inefficiency codes specifically, cat efficiency codes pop b/c the ECU has detected the delta value between the upstream and downstream sensor's output is out of whack, so you're better off taking time to confirm it's not the O2s first, or just replace the O2s and if the problem continues, you know it's the cat. A lot of people don't want to spend the $$ to replace the O2, then the cat, but it hurts just as bad when you replace the cat only to find it was the O2s!

A lot of times - and someone said this before, maybe in your other thread - it's commonly the downstream not properly detecting exactly how much was really filtered out by the cat. But it can also be caused by the upstream not properly sensing the combustion mix before it enters the cat. The latter of those two can lead to all kinds of other issues with fuel/air ratio, burning rich, etc. which can cause a cat clog.

 

Rather spend the money for O2’s first. Thank you for this advice.

 

Either way, hit us up with results. Always good in case someone finds this later in the same boat and, you know, statistical purposes.