OK i have a 04 Rodeo 3.2 rwd, and So lately my CEL has been coming on and off. I stopped at shucks and ran an OBDII test on it and came back as a p0420-Catalytic converter below threshold (Bank 1) The light will come on for a few days and than go off for a few days, what does that mean? Is this something to really worry about it right now? Is there a way to tell which Cat/oxy sensor needs to be replace? any help would be great