thanks for the reply aidan i did think it was unlikely to be the cat which is why i checked the injection duration which was ok? I did also wonder if it would stay open loop with a lambda fault logged, could this be enough to cause such high co readings even with respectable injection periods?? as i said before the heater wire (from pcm) has voltage until you plug in the new sensor so either high resistance or a short somewhere? really need the pin data to check at the pcm behind the head light so if anyone has this i would appreciate a peek! thanks again for reply.
cheers