Thanks for the suggestions so far everyone - just been under the car, fixed a few things and went for a test drive, the report:
That is really strange then, the engine is always doing some trim adjustment, even minor. It's like your O2 sensors aren't doing anything.
The other thing that is way odd is that your precat O2 voltages are not fluctuating. They should flip every few seconds from low to high. Yours are sitting at 0.45. Like it's running in open loop. Which it shoudn't be at 79 C.
I checked, the bank 1 sensors were connected... to each other
. Just as Sailor24 said - I'm not sure we can get much from the readings prior to this post.
Screeners of INPA don't really tell me much because they all look the same healthy unhealthy the trims usually show perfect. I did notice a couple of odd numbers first is your voltage. The second is the MAF reading bottom left of Analog 1 Total HLM. I have little faith in INPA because the scale for that is claimed KG/HR and the bar goes to 100. I have compared that number to my scanner I am pretty sure that is calc load as a percentage. Our cars use way more air than that even at idle. Just off the top of my head I think we use more than 700 kg/h at WOT, what good would a scale of 100 be? Actually I think it is way more than even 700 but don't remember and to lazy to do the math.
Anyway the point I am getting to is that number appears high it should be 18 -20 at idle. How old are your MAFs and have you done a road test for them? What were your results?
MAFs are about a couple of years old now, but this thing has barely turned a wheel in the last year because of all the fun I've had with the crappy shop I asked to diagnose a coolant leak with the motor. I'll attempt to do a MAF test at some point.
I checked the fuel pressure regulator vacuum line - it seems connected OK at both ends.
The result of reconnecting the bank 1 lambda sensors is the car definitely runs worse, at a constant throttle, (under ~2k RPM) it surges. It's not so noticeable above that.
Got some new codes and analog values, interestingly I get lambda regulation codes for both banks now, and the car still thinks the lambda sensor on bank 1 is bad - I wonder if it's been killed by the bad fueling caused by it being disconnected for the couple of hundred miles I've done when testing.
First up, codes (I reset these before the test drive):
Video of analog values - note how bank one seems to report OK then drops to zero @ 55 seconds?
Other observations, bank 1 smells really rich.