Which bank is which?

Should I replace converter or try to clean it? If replacing, which converter is bank 1?

 

I believe that on the V8 it is on the driver side and the V6 is on the passenger side.
I believe that a bad O2 sensor can give a similar fault.
Cleaning a CAT is hit or miss.
It is worth a try if you have more time than money.

 

How about replacing the downstream 02 sensors before anything and seeing if the code returns? Also clean MAF, replace air filter if necessary and clean the throttle body plate.

Bank 1 is on the driver’s side. Bank 2 passenger side.

 

Did this on a Camry for that same code 6 years strong

https://youtu.be/TxUya70kkQk

 

First, please, ffs, update your damn truck info to say if it's a V8 or V6 and 2WD or 4WD (Vehicle one-line field HERE). We can't help you if you don't help us.

Second, cat cleaners are bullshit. Complete and utter bullshit, gimmick af.

Third, 'cat efficiency' codes are often a red herring, and the actual problem is your O2 sensors aren't sending correct data to the ECU. The rare exceptions to this are when you've let a bad condition in the engine go for way too long, like letting things burn rich, foul, etc. due to intake leak, old plugs, etc. and that allowed the cat to clog up faster. Trust me, we've saved plenty of other folks money on this.

Before you waste time with replacing the cat, do yourself a knuckle-busting but money-saving trick: Assuming you have a V8, swap both O2 sensors from driver side to passenger side, clear codes or leave neg battery cable off for 10 minutes, then drive around and see if the code follows. If it does, the problem isn't your cat - replace both O2 on the bank that's now throwing the code. If it doesn't follow, replace the cat with OEM or an aftermarket brand that is known to NOT throw codes.

 

Which aftermarket brand does NOT throw codes? Already ordered O2 Sensors (Denso) from RockAuto.

 

Install O2 sensors before you go there, but I posted more info in your other thread/comment on the topic: So far, members have had luck with Magnaflow, Walker, Summit Racing's store brand, and OEM. I wish I could remember which brands have unexpectedly thrown codes for folks, but my brain only holds so much info, and thought it was more important to remember the ones that don't.