been down that path . Was with 2000 PRIZM ( Corolla ) that had little over 70,000 miles on it when I decided to switch to a synthetic using MOBIL 1 5w-30 and then a fill of PLATINUM 5w-30 and then PENNZOIL S.U.V. 5w-30 blend and then back to regular PENNZOIL 5w-30 where it stopped consuming not long after . Was close to a quart at first and gradually slowed down as weened it back to PENNZOIL conventional 5w-30 . Never used much , if any oil before the switch . Crazy . Good Luck .