Error code P0420

Hey everyone. I have a 2008 Toyota Tacoma SR5 2.7l 5sp with around 170k miles. Recently my check engine light came on and it’s putting out a P0420 code. Anyone have experience with this? I googled it and said it’s a clogged cat. The guy at autozone said it could be a leak from the manifold. I know I have zero power, and when I hit 3k rpms it falls on its face and sounds like it back firing. I do drive around 25 miles one way to work and do not have another vehicle. Any advice? Just spend the money and replace the cat? If so, what’s the best place to order one from? Thanks in advance and appreciate your time.

 

Welcome aboard Brandon

 

Thanks. I basically have the same truck as you except it’s an ‘08 and red.

 

I had that code. Turned out to be a bad gasket connecting the cat to the Y pipe.

 

Pop the #4 coil out with a 10 mm and see if it’s wet with oil or dry. If it’s wet you need new valve cover and (more specifically) spark plug tube gaskets

 

Check performance after removing the air/fuel sensor. If that improves performance your catalytic converter is clogged and should be replaced.
Lot's of other things throw a P0420.
A muffler shop can tell if the cats are shot if you lack mechanical abilities.

 

I've got over 300k on my cats and they're still doing their job.
My code popped up shortly after the motor was swapped. The mechanic and his snap on scanner were adamant that I needed cats.
I didn't believe it. I eventually found the leak. $30 for gaskets is better than a new cat.

 

So, this intrigues me. I've had a P0420 code for quite some time - it's a 2002 with a 3.4L. No power loss, no characteristic smell of a bad cat, no noticeable change in general performance or fuel economy. I have, however, found that I'm having to add oil and there is oil spilled out across the side of my engine. I've been cleaning and watching and trying to figure out where the leak is coming from and all I've determined is that it's high on the engine. You're saying that if I pull a coil and it's wet & oily I need one or two new valve covers?

 

Spark plug tube gaskets specifically but of course change the valve cover gasket, as well since you’re there

 

Thank you for the tip. I'll be doing some investigating!

 

Brandon, Welcome to the Family!