How are some you guys getting o2 readings with leaded fuel and running cats?

 

Stock narrow-band O2 sensors are rated to survive 50 hours of operation on leaded fuel. They do not die an instantaneous death when exposed to lead. That catalytic convertors, on the other hand, have virtually no tolerance for leaded fuel.

Wide-band sensors are also capable of maintaining accurate readings for a reasonable period of exposure to leaded fuels. But like the narrow-band sensors, their life span is shortened.