This is why my check engine light is on.

I have a 2000 Civic DX. I change the o2 sensor at the top and it went away but now its back on. Think I'm going to replace the whole cat converter and the senors on the bottom.

Anyone know of the best place I can order the parts online? I walked into AdvanceAutoparts and hell I felt like I was teaching the guys in there about cars. AutoZone I try to stay away from because its bad enough when you walk into a car store and see a chick in heels behind the counter who is asking for help on returning an item. (got a free o2 sensor out of it tho heheheh)

But seriously I need to know the best place to shop for a aftermarker cat converter (the one underneath the car) along with the o2 sensors for it. Should I just replace it factory parts or is there something that will give me more bang for my buck.

 

Hey bud. Go to a junk yard and get a used one. Or buy nice upgraded exhaust system that replaces the cat with a down pipe.

 

ok I went to a pull a part before and they told me they do not sell the cat converter because its against the law or some ****. I hate pull a part anyways.

Now when you say a upgraded exhaust system what exactly do you mean? I am fairly new at repairing my own civic however I am a fast learner and very good when it comes to attention to detail. I am just not familiar with the exact parts on the cars.

The exhaust system is the total pipe line that runs from the engine underneath the car right? so im guessing the new exhaust system comes with the "downpipe" that replace the cat....

not exactly sure what a downpipe is. sorry noobie here

 

You cant buy used cats it is against federal law, unless you know someone like I do. Got a EM1 cat for my B series swap for a song. PO420 is a cat efficiency below threshold, you need a new cat. On the Lx D16Y7 motor the cat is part of the exhaust manifold so you will need to replace the whole thing. Best place to look is places that sell only exhaust system parts. O Rielys and Auto Zone are fine though as well. If you replace the exhaust like Honda.Salesguy is telling you to it will delete the cat and you will still get a PO420 code.
I would do the Lx to Ex exhaust mani and cat conversion. For this you need a D16Y8 header and cat (2 separate parts) and an O2 sensor extension harness that you can get from PasswordJDM. You will also need to have the exhaust modified slightly since it is too long for this setup or get an Ex catback.