Hi if i could get some advice Id appreciate it Ive an 04 Corsa c 1ltr had an intermittent fault code P0136 1 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2) so changed the 02 sensor out fault code has gone but the sensor is reading 1.100mv too 1.500 mv and is rich all the time on Opcom have warmed the engine up this seems off to me can anyone advise as its in for an nct test on Weds