Sorry to drag up such an old thread, but I have had an Astra in with misfire cyl 4 and to cut a long story this had a split exhaust in the flexy part immediately before o2 sensor b1s2 and it was running very lean at idle.
KTS doesnt have the ability to reset adaptions, can that be done with vaux com or is tech2 the only option ? An exhaust + extended road test sorted it btw.