A MOTHER AND HER TWO CHILDREN WERE FOUND UNCONSCIOUS INSIDE A NISSAN PATHFINDER IN A PARKING LOT OUTSIDE OF THE PUBLIX NEAR KINGS HIGHWAY AND THE INTERSTATE YESTERDAY AFTERNOON.  DEPUTIES NOW SAY IT WAS ACCIDENTAL CARBON MONOXIDE POISONING THAT CAUSED THE WOMAN, WHO APPEARED TO BE ABOUT FORTY, AND THE TWO GIRLS, ONE A TEEN AND THE OTHER YOUNGER TO BE OVERCOME.  THEY WERE ALL TAKEN TO THE PEACE RIVER REGIONAL MEDICAL CENTER IN SERIOUS CONDITION.  AUTHORITIES SAY THEIR CONDITIONS HAVE STABILIZED, BUT THEY WOULD NOT ELABORATE FURTHER.  DEPUTIES DO NOT KNOW WHAT THE SOURCE OF THE CARBON MONOXIDE WAS AND THE INVESTIGATION IS ONGOING.