I read the posts on the P0420 OBDII code but was unable to come to a conclusion. It just so happens I'm getting the same code on a '98 V6 SE and I would like to know what it turned out to be. Can anyone help me?

V6 SE Contour with all the goodies, Halo Plugs, Direct Hits, Resonator removed.

1972 Ford Classic Bronco, Heavily Modified