My secondary offset driver's side o2 sensor has stripped threads in the cat. It isn't leaking but isn't fully seated (3 threads proud). The OBD port shows the voltage responds correctly to loads but fluxuates at a lower voltage than the other side. .25V-.5V vs .5V-.75V The other 996tt's I've checked run .5V-.75V equal on both sides. My car is a GT2 and has thrown P1155 twice. Is the sensor voltage the cause?