Placing  it here not to trash the proper sections with something silly like this Besides, seems lots of people read here.

My dear LSU connected to Zeitronix Zt-2 seems to be reaching its EOL, unless what I am seeing is normal, hence the question. Despite the sensor being warmed up according to Zt-2 (I also leave it on ignition power for at least 30 seconds) it gives crapish readings for the first ~2 minutes of running, even on practically warm engine, just freshly started. I think this could be low EGT related (LSU is mounted post-cat), because as soon as the average EGT (the model one) raises a bit, the readings become sane. (Also the engine is still open loop, perhaps the ECU thinks the same about the narrow band readings during the time...) By crap readings I mean they are off by 0.5 to 2 AFR either way and depending on the dynamics (when I see 17AFR dip on slight acceleration this can't be right, I would feel it, the engine runs smooth). Also in general the readings, even if good values after warmed up, seem to be slow to react.

Now, this could be all normal (I do not remember how it was on my previous car, the ECU was not as fancy as ME anyhow, AFR was more all over the place in open loop), simply cold running and post-cat placement, but the sensor is 8 years old - 5 running on my previous car and doing 60kkm, 3 years on the shelf. Not sure what an average life span of these things are.

Another thing - what would be a cheap but decent WB controller alternative to Zt-2? It has one serious issue for me - it shuts down during cranking (always did) and this can't be fixed unless powered from another source. I would need something with at least linear 0-5V output, but a serial connection with documented / known protocol would be better.