Just whistling "Crime of the Sensory"

and thinking about earlier in this thread - I'll take the new sensor out & inspect it soon to see if the sooting has been eradicated.
If yes, then the ECU responds to a perceived 'lean burn' from the sensor by adding more fuel to an engine that really is running OK, causing overfuelling and sooting.
if no, then there's a problem with the air metering or air/fuel ratio (Elanscan results show O2 sensor voltage fluctuating between near zero 4.5v during use).
Songs: 3 Result For sensory as Song Name
Song Title:
Parting of the Sensory - Modest Mouse
Sensory Deprivation Adventure - From Autumn To Ashes
Extra-Sensory - Superdrag
Update on sooting: new sensor installed, no sooting now occurring so it would appear to be a correct assumption that if the O2 sensor output is low (lean) due to failing sensor the ECU reads the lean signal and feeds more fuel to the engine causing an overly rich mixture.