Background:

I use a permanent install LC-1 logged through my IX ecu. the sensor has been installed in the car for 17,000 miles with the last 6,000 or so running e85.

Symptoms:

Earlier this week while doing some logging with EvoScan it appeared that my AFR had gone over one point leaner compared to my logs the week before! I checked a few Items (injectors, fpr solenoid, pump) and everything seems to be in correct working order.

After the car mechanically checked out ok I did a free air calibration of the unit and logging seems to have returned to "somewhat" correct levels.

Current Issue:

The sensor seems slower to respond that before, you can see in the graph below where I let off the throttle and the AFR still hovers around 13 and finally jumping back up to 22. You can also see how under load the AFR seems to be jumping all over the place! I did some quick searching and it seems that this type of behavior indicates a failing o2 sensor but because this is my first sensor I am unable to determine if the sensor is actually failing.



What do you guys think?

 

y not recalibrate and try again?

 

short answer: yes it is failing.

how long you have? who knows...

 

I had the same issue.

conclusion:
I had to change the sensor after 6 months of usage.

Now it's working fine again. I mounted it a little bit more downstream to reduce the operating temperature

 

When your sensor goes very slow to respond and starts jumping , its time to replace it. Mine was behaving the very same, would go very lean, then slowly goes back to normal and then idled at 12.5,etc.. Mine failed after less then 4000miles, got a replacment from VW and its back to normal now