BB195

I am having a problem with my 1996 turbo 1.8l miata. I am currently switched over to stock with the stock ecu. I have swapped out both o2 sensors and still get the code for my rear o2. The wires from the o2 sensor to the ecu have continuity and is about little to no voltage what do ever. Have swapped spark wires and coil pack so far. Still have the code