Idling Oxygen Sensor: Causes of -2.4mg/H Reading

Evening!

Today, after adjusting the pump voltage curve (which eliminated the jerking), I noticed that the idle speed control is showing readings of -2.4, -0.4, and approximately 0.

I had the nozzles replaced just six months ago.
I have to say that I only swapped the cartridges, without pressing them in. *Embarrassed *
Can an incorrect fuel injector nozzle pressure cause this correction of the fuel injection quantity?
Starting behavior is perfect, performance is excellent, and fuel consumption is normal.
Six months ago, the values for the idle speed control were still within the acceptable range.
Could it be the new injector nozzles causing the problem, or clogged injectors due to poor fuel quality? What's the best way to clean the injector nozzles without contaminating them internally?


Best regards, Christof.

"First, I would have the injectors cleaned and the spray pattern assessed. I've personally had new injector nozzles where the spray pattern wasn't correct. Either something went wrong during assembly, even though careful work was done (perhaps due to dirt?), or the nozzle itself was defective. I'll definitely have them cleaned and checked again soon. (Which, unfortunately, no one wants to do here in the far north)."

Regards,
Guste.