ok so i replaced my o2 sensor cause the old one was f'ed. all runs the way it should now, but now my dashdaq reads knock no matter what i do or if im in tune or stock. with the old one i got a little knock when i did light acceleration and non on wot or any other time. now i see it at idle sometimes, but that seemed to have stopped, i see it at all throttle positions. mind u at wot its only about .7 knock retard, but why am i suddenly seeing more knock when i changed my 02 sensor? and should i be worried?