CEL! p0420

[EM1 Kidd]

I drive a 99 Civic SI and my p0420 check engine light cut on. My car lags out of first gear and doesn't pick up until after 3k rpm. I don't have a Cat on my greddy exhaust. Do I absolutely need to buy one or is there any tool or part that I could buy so the CEL no longer appears. I've replaced my spark plugs fuel filter distributor cap and rotor and the lag remains. Everytime I erase the code it doesn't appear until I launch or warm up my tires. But the lag remains even without the CEL light on. I've had this same code the past 3 times I've checked. My car doesn't seem to be running at full potential like when I bought it. Any help would be greatly appreciated and sorry if this is really dumb question but this is my first car and i would like for it to run perfectly.

[DeathLens]

http://www.jhpusa.com/store/pc/viewPrd.asp?idproduct=2952&idcategory=381

it's throwing the code cuz you don't have a cat. put this on your second o2 bung and put your sensor in. Orrrrr buy a cat and stop polluting. 1hp is not worth it.

and check out em1crew.com

[wallendiaz]

http://www.jhpusa.com/store/pc/viewPrd.asp?idproduct=2952&idcategory=381

it's throwing the code cuz you don't have a cat. put this on your second o2 bung and put your sensor in. Orrrrr buy a cat and stop polluting. 1hp is not worth it.

and check out em1crew.com

I have the same car and the same problem, this method really work for you???