Hi John,

>>>one silver bullet coming up<<<

I suspect your silver bullet is tarnished as the one already shot by previous posters is much shinier in my experience.

This problem is quite well known now and I have to admit the first time I experienced it I spliced in a separate earth independant of the ECU. But later I realised it was the rear sensor pulling the earth up sometimes as high as 5 or 6 volts!! Affecting both sensors. And as already stated the ECU can only report an output in live data of around 1.2v.

I would advise it better to eliminate the lambda sensor fault by testing as described earlier, then and only then would you look at the possibilty of an ECU internal earthing issue.

Regards,

Mike