I'm going to start tracking my mileage like I used to do in the past everytime I fill up (couldn't find the info for the previous fill up). Took 55 liters and got 360km's, which was 4 highway trips which was about %85-%90 of my mileage. Will let it go for another tank, then unplug or replace the O2 sensor.

Is there a way to test the temp sensor at all?

 

Here is some of my latest fill ups with the most recent being the top. Does this seem acceptable, high/low? I had replaced the o2 sensor back in January after starting this thread.

 

Depending on the driving that you do, that doesn't seem too bad.