First thing is to understand that a P0147 does not mean the sensor is bad, it is pointing to a fault somewhere in that entire circuit. Check for 12V between the BLK and PNK wires right down at the sensor connector on the harness. If that is OK, then I gotta ask... were these all new sensors you threw at it, or used ones of unknown value? If the 12V is not down there between the two connector wires (get the hint, checking between the PNK and some chassis ground is not "good enough"?), then you have to start tracing back both the power and ground with the multimeter. There is a fuse (ENG 1) for that power (PNK) wire, so that should be checked before even going down to the connector, but I doubt that is bad since it feeds all the other O2 sensors and other stuff as well; I think there would be more codes than the P0147 if that fuse was bad. Obviously, be inspecting for any broken wires or corrosion in-and-about that sensor harness connector.