Originally Posted by BigManMopar
IV got a 1998 dodge ram 1500 4x4 with a 318...just recently I pulled the motor apart and did head gaskets and intake gaskets...it runs great and then the other day I got a P0420 code saying low catalyst efficiency bank one and I'm not sure if the O2 sensor is shot or if my catalytic converter messed up when the truck is running I can hear what sounds like something clapping around inside the catalytic converter. Anybody know anything that would help me diagnose the problems...is there a way to re-calibrate the O2 sensor?
Sounds like your cat has finally died, but a clapping sound could be an exhaust leak. But with the age of the truck and all...