Those are very good numbers for a M103. The NOx leads me to believe that the timing map is retarded, but like most KE fuel system models, HC is high relative to the other emissions.

Does your engine have EGR?

I can't make any sense out of the O2 readings. Air has about 20 percent O2 and the exhaust gas should have near zero. In CA the O2 readings are given percent and an efficient catalyst will yield 0.0%. If it's more, like 0.1% or 0.2% the cat is not working at maximum efficiency, often because it is not hot enough.

One tenth of one percent is 1000 ppm, so even if the reading is 0.0 percent, there could still be enough O2 in the exhaust (a few hundred ppm) to promote more reaction if the catalyst is hotter, and this will reduce the HC number.

I wish the O2 readings were in ppm.

Duke