I' m install a header on my car and these codes just comes up, what can i do ?

 

what year is your car?

and what headers are you speaking of?

 

P0420 is a common cat efficiency code. Did you use a nonfouler along with the stock sensor? Again year make and model also brand of header are you using. That info would sure help

 

P0420 is BANK 1 catalytic converter, your o2 sensor after your converter is picking up fumes that have not been cleaned by the catalytic converter...meaning your whole catalytic converter is no longer effective and needs to be replaced (only if you need to do an emissions exam for your car)

Im gonna take a wild guess and say p0430 is BANK 2, so both your first and second catalytic converters arnt doing there jobs

I highly doubt they both went out the same time so im going to say remove whatever you installed and see if the codes go after driving it around

 

2008 acura tl and yes i use nonfoulers but only on primary oxygen sensors, the headers are the ones that comes generic for this engine, that is the same for 2004 accord

 

3G TLs headers are casted onto the heads; so there isnt any heders you can bolt on to the TLs. You must have meant the cats.

 

That's your problem.

They are not supposed to be for the primary o2 sensors. They are meant for the secondary.

 

Im gone to try this, i let you know if works
Thanks