P0420 error code 2001 Tacoma. I have some questions!

So the P0420 (bank 1) error code is coming up and my mechanic is telling me that one of the two catalytic converters my truck has needs to be replaced.

Recently this morning my truck left on idle was revving on its own when stopped at the light (to about 1700RPM up and down) after driving it a few miles. When I pressed the brakes my truck engine would stutter a bit and continue revving on its own when parked. Wondering if this could be from excessive fuel trim due to a vacuum leak or a bad cat? I recently replaced my radiator. There are no coolant leaks at the moment and the 02 sensors are working just fine as well. There are some valve cover leaks but I can't seem to determine where exactly its coming from (the engine block is looking pretty dirty now due to it). Are the valve cover leaks really bad?

Does anyone know what a catalytic converter cost would be for a 2001 toyota tacoma
(2l na i4 double overhead cam engine)? i'm trying to figure out if I could get a good quality one somewhere wholesale price? since my mechanic is quoting me around $1400 for a new cat.


any help would be greatly appreciated. Thank you.

 

I had the same issue on an 2004, OEM Toyota cats are the best and most expensive, although the second choice would be Magnaflow which seem to work for most peeps.stay away from the Universal types cats that are welded on they creat more problems. if you search the GEN1 forum under cats you will find a lot of infos on the subject.

 

Your hunting idle most likely is from a dirty or sticking idle control valve (IAC)

As for the cat code depending on mileage history of the truck possibly having a bad misfire in the passed could have caused it to go bad. There also could be an exhaust leak letting in air passed the rear o2 causing the light to turn on. I'd have your exhaust smoked and checked for leaks first.

 

on my 03 tacoma 375k the throttle body was just wore out and that was causing the idle to hang and then creep up... $50 wrecking yard TB and all good. try this before you replace your cat(s)

 

Careful what you buy when it comes to a cat, california laws are pretty strict from what i understand and a univesal cat could be an automatic fail for emissions

Bay area is cali right?

 

A lot of time the 0420 is not a bad cat but other things like mentioned above.

here's one option (rear cat) :

$203 Walker Ultra EPA 53432 Direct Fit Catalytic Converter for Toyota Tacoma

https://smile.amazon.com/dp/B000VL1...TF8&colid=2AP5NQN4CXKTY&coliid=I2SFR32JW0I0JN

 

Cats are probably fine.. Read here
https://www.tacomaworld.com/threads...omers-of-the-p0420-code.396763/#post-14489556