I have a 2000 Tacoma Prerunner TRD V6 Auto and I've been getting a P0420 code a lot lately. Up until last month I would get the code every 4 or 5 months but lately I get it almost every other day. I clear the code and in a day or two I get the code back. I just had the truck smoged last week and it passed so I don't think it's the cats. Any suggestion on what I should look for/where to look. Thanks.