Hello, I have a 2002 Toyota camry with 100,000 miles on her. The car has a 3.0 V-6 engine. I would like to know if I should continue using synthetic oil or should I switch to High Mileage Oil? I don't leak or burn any oil in this vehicle. I also have a 2007 camry four cylinder. I'm using synthetic oil in this vehicle also. She has 90,000 miles on her. She burns a quart of oil every 1,600 miles. Should I switch to High Mileage Oil and a different weight in order to stop or limit the burning of the oil?