I pulled a P0420 bank one yesterday on my zetec. Reset the computer and goes away until i have to sit in traffic after work. When i come to a stop after driving the car a lot the engine sometines stumbles, doesnt stall though. Other then that everything is ok. Im thinking bad rear O2 sensor, its all rusted up and evrything. Thanks

Nick F.
01 Focus ZX3 MTX
borla, eibach pro kit and dampers, dual guage pod (a/f and volt), jvc kd-sh99

96 Contour GL atx-zetec
Yes its a zetec, we were here before vtec, so we are not copying!