About 2 months ago, I started getting a check engine light in my 2004 Honda CRV which turned out to be a P0420 code. I replaced both O2 sensors and the error went away...until yesterday. Now, the same P0420 code is back again. I'm thinking the next step is to replace the catalytic converter. I can buy an aftermarket part for about $300 and replace it myself. But, I wanted to see if anyone else has had the same experience with a P0420 code. Could there possibly be any other issue that might cause this error code? Thanks!