i searched and best i can tell high mileage 3.0s use oil by the quart. my CPO 06 seems to have burned thru 2 quarts in 7300 miles. it only has 32k miles on it. am i to understand this is the norm? i plan to change the oil later this week, should i add an extra 1/2 qt? anyone running 5w/50 mobil1. it seems to help in the 2.8l track rat.