So I've been tinkering - tried to get a reading from the Oxygen Sensor - nothing.
Got a reading of between 6.0 and 10.5 in Volts for the X11 diagnosis pin between pins 2 and 3, (duty cycle) which I think comes out at anything from 50% to 25%?? with 50% being 6.0 - as max is about 14?

I then unplugged the O2 sensor, and it had NO effect whatsoever on the Duty Cycle reading?

On a side note, my distributor is adjusted well, the EHA may be a little high? And I lowered the idle speed right down as it was far to high (2000 in P sometimes). Trouble is now there is a rattle and the idle is slightly rough in Reverse and at 750RPM...

Is it possible that the O2 sensor is whats causing the mass fuel consumption? Seeing as the other things mainly focus on acceleration (EHA and Distributor settings) most of my traveling is highway KMS....

Hope this new info helps me somehow... Cheers folks.

__________________
1971 280SE - The S Class
1974 280CE - Sterling
1988 300E - Stanley