Hi mr. Scotty
Afi from Australia. I recently brought a honda accord 2008 2.4L 4cly with 165k km.. 1 week after buying i i saw a engine light coming. I check with readers its shows code "p0420" catalytic system efficiency below threshold. So i don't know anything about car. I went to 2,3 mechanic to see whats the solution. 2 of them said that i need to change the catalytic converter which is very costy here.. but 1 of them said i don't need change it and he will fix it with 350$ au and no engine light will come again. So i went to that route.i don't know what he did but after he fix the car ,there was no engine light. But after that day my car went to lean condition. 0 to 40km/h talking to much time. Rev is going over 3000 but no speed gaining also no speed in litte up hill..engine working too much but no performance...what's should i do and should i change the catalytic converter because i am sure he did not change it..
And also the code said bank 1
P0420 usually has to do with the catalytic converters system. It could be:
1) A clogged catalytic converter, which would need changing out.
2) Bad oxygen sensors.
Depending on emissions regulations in your country, you could straight pipe your system. It might not get rid of the codes, but your car would run fine (yet pollute because there’s would be no catalytic converter.)
To be honest though, without seeing the car or knowing more, it really sounds like a clogged catalytic converter.
Thanks for your reply..
So do you thinks because of the clogged cat my car is running very poor, lean condition, should i clean the cat or replaced it..
Thanks
First I would check if the engine is running lean or rich. If the problem is upstream, you will have the same problem down road. And if everything is okay, change the cat.
You can try to clean it, I personally don’t know how to clean one.
The car is definitely running lean. Its very noticeable...so changing the cat can solve this problem as well