99 Honda Accord P0420

[shalomhome]

I have a 99 honda accord ex 4 cyl. last year at 100,000 Mi. my CEL came on. i don't remember the code it showed but auto zone checked it and said it was the Cat. and o2 sensor at the cat. so i replaced them both. both part were bought online and were called OEM replacement parts. the car has run fine since then. (It even ran fine before). last week at 114,000 Mi. the light came on again. want back to AZ and had them check it. it coded P0420. "Cat. Efficiency below threshold (Bank 1)" they said it is cat. again.
The car is running fine. nothing noticeable with anything other than the light is on. should i replace the o2 at the manifold now? i have read so much about this form online forums, i am confused on what to do.
someone who knows this well, would you please help?

[somick]

See if that info can help you

http://www.tegger.com/hondafaq/p0420.html

Good luck,

Sam

[shalomhome]

Thanks for the info. i will try it. do you know if it is common for a cat to go out 1 year after installation? it is an after market but it is also an OEM part. or at least it says it was.

[somick]

Originally Posted by shalomhome

Thanks for the info. i will try it. do you know if it is common for a cat to go out 1 year after installation? it is an after market but it is also an OEM part. or at least it says it was.

I have no idea! May be somebody else with knowledge in this area will chip in.

Sam