Complex sentence: Personality issues arose once again and Vincent was fired following the "Lick It Up" tour, due to excessive guitar soloing at a concert in Quebec, 1984 and was replaced by Mark St. John (birth name Mark Norton).
Split into simpler sentences: Personality issues arose once again and Vincent was fired following the "Lick It Up" tour, due in part to excessive guitar soloing at a 1984 concert in Quebec. He was replaced by Mark St. John (birth name Mark Norton).