I recently got a code p0420 , I here that this is most likely the cat. I also started to sometimes get a sulfar smell? My question is what's the best place to find a replacement cat? The car is bone stock minus a Short ram intake. Thanks guys

 

forgot to mention also guys that my mpg seems to be getting worse also. Does this sound like the cat? Or maybe 02 sensor?

 

Does the car bog at all? Bad gas mileage can be both the sensor and the cat. The smell is definitely the cat and that can make your o2 sensor go bad. Since you are not in CA, you can get it replaced at any local exhaust shop.

 

I wouldnt say it bogs. But maybe feels a little sluggish. Whats a good brand to go with? Also should i replace the 02 sensor while im at it?

 

replace the cat first...if mpg doesnt improve, its likely the 02 going bad as well. how many miles on your car?

 

My cat just recently went bad on my 98 ex and my car did feel sluggish. but i just got a new cat and its running way better now.i Bought a magnaflow cat online for 150$ and installed myself idk if they fit for Si's you should look into it. but you should first find out if its the sensor.

 

You'll have to get a CA legal cat unlike the other 49 states CA requires it. The sulfur smell tells me its not the 2nd O2.

 

im from pa, Im a little confused what your saying?

 

This is what I was thinking to do

 

Sorry I was reading another post in here and thought you were in CA. Like said above replace the cat, clear the code and see if it comes back.