The car is a 2002 impala 3.8. Its a V6 but the system is counted as one bank only, as in one pre cat o2 sensor, one cat and one post cat o2 sensor.

Im using the torque app on my android and connected it via a BAFX bluetooth OBD-2 scanner.

The voltage graph when seen at idle stays at lean position. about 0.15V, when tested in driving, it goes go to 0.45 - 0.50V in some conditions for a brief moment (hard run) and then comes down to 0.15V and mostly sticks there. The front sensor is switching between 0.2 to 0.8V constantly if I plot a graph for about a minute or two. I did try leaning and richening the engine and I can see the front one responding immediately. The rear one also responds by going to about 0.7V and staying there for a second or two.

The car runs freely, no strangling, no hiccup etc, the cat does not rattle and neither does it seem overheated.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)