Bedlam wrote:if you already changed your cat and end up with a P0420 code, your next stop is a new downstream 02 sensor. I just replaced mine on my 03 and was able to finally pass emissions.
If you still have troubles, you can use a non-fowler extension with a few bits of steel wool. This takes a little patience and drilling though to make work right. The cat and 02 sensor are your first stops though and will most likely fix 95% of the P0420 codes out there.
This code cam on in my '04, and I did the anti fouler trick. CEL never came back on.
IMO, a P0420 equals anti fouler trick.
