Ageing O2 Senesor Code 16
 

I just pulled a O2 sensor code 16 using my Durametric. I experienced the same problem a couple of weeks ago and ordered 4 new o2 sensors, the Bosch before and after sensors. The car is a 2003 Boxster S with 51,000 miles. When I checked the readings the volts behind #1 were running low at like .07 to .1 volts to the #2 side reading 0.61 to 0.71. Could this be a bad sensor or???