i realy dont know were to start but my 2003 venture started backfiring out of my left exhaust if your looking from the back so i tried plugging the ais system that did not work so ive been trying to adjust the pilot jets on each carb and while i was doing that for some reason my right exhaust started blowing out white smoke and black oil. i pulled all spark plugs which i just installed new ones less then a month ago for black oil on them and they are fine. there is no knocking or sounds like loss of power. so i kept on adjusting the carbs and i set all of them at 1.5 turns to start out but the backfiring was the same or worse. so while it was running the carb closes to the seat on the left side i turned the pilot screw all the way in and backed out just a half a turn and the backfiring stopped and so did the smoke and black oil. can anyone explain this for me. on the same carb if i go a full turn 1 time it starts to fackfiring and i go to 1.5 it gets worse so i go back to half a turn and its fine again. what puzzles me is that it started smoking and the black oil from exhaust. could i have caused this to happen just by adjusting the pilot screws.?
