Has anyone retprted a bad catalytic converter? I've jus chnged spark plugs and O2 sensors because of a P0420 code, before going any deeper...

 

have u looked up what 420 even is? what would an 02 sensor or spark plugs have anything to do with that?

 

P0420 is a code for "Catalyst Inefficiency". It is possible that the rear o2 sensor has failed or is out of range. If the o2 sensors doesn't fix anything you might have a bad CAT

 

I intend to remove my stock muffler and install a performance muffler. Can an expert tell me if the catalytic converter needs to be removed as well to increase horsepower?

 

i have a 2005 pacifica....had to change the catalytic converter....at that time the dealership told me it was under federal warranty....with 70K miles on it....i now have
102K miles on it...my check engine light is on...with the code that shows low pressure on my catalytic converter...what ever that means....it goes off....it comes on....no rhyme or reason.....does anyone know what needs to be done or if it is still under federal warranty cause of the emissions controls???

 

there is no such code for low pressure in the converters there is no sensor in the exhaust system that measures pressure. visit advanced auto and get the numbers they give u from a free check engine light scan

 

This guy may have had a PO129 code which indicates low barometric pressure. I had this code come on along with a PO 420 code.