P0421 warmup catalyst efficiency below normal (catalytic converter removal or replace?)

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Trom89
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Year/Make/Model: 03 Mitsubishi galant
Engine: 2.4 4cyl

P0421 warmup catalyst efficiency below normal (catalytic converter removal or replace?)

Postby Trom89 » Wed Aug 10, 2016 5:40 pm

Hey there, new to the forum and apologize if this has been asked before, but I've looked all over the place to no avail.

I recently got an error code of P0421: warmup catalyst efficiency below normal (bank 1)

I'm pretty sure the problem is my catalytic converter and my question is could I remove the cat and just run piping instead without having to update the computer? Or would it be cheaper to simply replace the thing?

No emissions testing where I live so don't have to worry about that. I have already replaced the upstream 02 sensor, but the car is still bogging down and hesitating off the line noticeably. Any advice would be great, thank you.


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