Any body have any advice on this? Looked it up and says high voltage on downstream o2 sensor.

Would this be a fault in the sensor itself or possibly a bad cat?

I have a 2003 1500 4x4 with the 5.9L. I have a cat back exaust. Single in, dual out flowmaster super44(it was free and it sounds good). oh and the truck has 106,xxx miles on it

thanks guys

 

i would replace the o2 sensor... first check all the wiring for exposed wire or a short somewhere or even get some electric parts cleaner and spray the sensor real good with it see if that helps