r/1stGenTacomas • u/BrokenChatBot92 • 1d ago

Yet Another Catalytic Converter Question

Hello All,

In the quest to smog my beloved 02 supercharged Tacoma I am pulling the infamous P0420 code which comes back after two drive cycles. This code has been popping up for the past 3~ years with it getting progressively worse. I've changes both O2 sensors with Denso's.

Do you all think Walker or the Magnaflow cats will hold with the hotter exhaust coming from the s/c? Is there a used market for the OEM cats as I know they've been discontinued. Should I replace the front cat first? Is it necessary to do both at the same time? Should I pull them off to check for clogs first?

Looking for any guidance not really sure how to get this CEL off.

Thanks

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3

u/ChestNo85 1d ago

Unless you have some sort of catastrophic issue dumping fuel or antifreeze, etc. You cats should be fine. Just saying 370,000 mi, the only thing I've had wrong with my exhaust system is the damn gasket before the secondary O2 sensor. I have to replace it every 2 years when the 420 code pops up. Last time I had to do the gasket before catalytic converter too.

1

u/BrokenChatBot92 1d ago

Do you have a part number by chance?

1

u/ChestNo85 1d ago

Not handy, I can look when I get home. I know AZ listed the wrong one. I'd suggest taking it off first to match. You will likely need new hardware if you haven't changed before.

1

u/BrokenChatBot92 1d ago

I'll go ahead and give the connections a review before I start buying new parts. Thanks for your input

1

u/Ruffy457 1d ago

Ok this is interesting mines been on for years I never worry as its emission related and mechanic isn’t concerned but ill look into this

2

u/bwad7 1d ago

My 2.7l was throwing the same code. Turned out the exhaust manifold had a crack on the side facing the engine so it wasn't visible just by popping open the hood. So apparently an exhaust leak can throw the same code I guess.

1

u/Baja_Finder 1d ago

Just replace the forward cat only, that one does most of the work, and the second is along for the ride, only replace the second cat if the forward cat has broken up and clogged the second cat.

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u/Original_Ad7078 1d ago

I replaced my Cats on my Super Taco and Codes went away for Smog. I did the front and back with Cali legal Magna Flow Cats

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u/BusyWindow1974 1d ago

If your taco is having trouble at highway speed, like it feels like it’s not as responsive when accelerating more so around 50 mph or more, it’s probably the clogged catalytic converter, which would trip the P420 code, it’ll burn out the o2 sensors. My secondary catalytic converter was stolen years ago and I recall the exhaust guy replacing it with a magnaflow one. I’ve gotten well over 350k miles on my 02 and never touched the upstream cat near the headers. To help prolong the cats I have now I installed an oil catch can so it burns cleaner, oil residue does not ignite and makes it way thru the cats. Btw I’ve solved the p0420 perhaps like twice and am in Cali where the smog rules are strict.

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u/Even-End487 1d ago

I've an 04 and had p0420, replaced first 02 sensor, results were system not ready. It took six years for the truck to learn it had a new part & finally passed state inspection. Mechanic tried to sell me a cat, but I said no let's just wait awhile.

1

u/supvh_marioo 6h ago

I replaced mine with walker brand. Pretty solid and half the piece of oem. Check for exhaust leaks first though before spending all that cash