Those comercial Widebands ALLWAYS show some errors... a friend of mine wich works in GM made a bench test with inovatte, and some other brasilian wideband controllers compareted with Oribas and they show something about 0,03 points derivating from Oribas, and this without having pressure (backpressure in engine)...
If STFT is lower than +/- 8% (it shouldn´t be 0%, has to oscilate next to, but never allways equal zero) you probably has all set well
Yes.. at work we have an Endo gas furnance.. It has never been calibrated lol.. I wonder how much nature gas they have wasted through the years