Johnny the Fox

I added my downstream oxygen sensor and connected it as per the wiring diagrams, but when I check the operation of it with my PScan, the voltage stays around 4.5 volts , with the now wired EML lamp on the dash coming on after a few days driving.
I swapped the sensor for another one and same thing occurred.
Thing is when I disconnect the sensor, the values drop to around .90 V, which I assume to be a default.
I have taken some screen shots of my laptop showing fault codes and running values of the sensor.
Just to add, the car has alloy manifold, 135 cams, 52 mm alloy throttle body and blue injectors. I am sure that standard injectors for Mk 2 F and TF were black, the blue ones are 160 ones.