I inherited my Dads 2002 highlander with 3.0 v6, It was using about a litre of oil every 500k, the odometer had 260000k on it, after a bit of research someone mentioned the use of Seafoam oil additive. I thought what can it hurt?? I added the recommended amount to the oil and continued driving it adding oil as needed. Well the consumption decreased so I then changed the oil to a 15w40. I have since clocked over 6000k, 3500k of that towing a small holiday trailer to the west coast through the mountains and back. I check the dipstick today... down maybe 1/2 a litre. I believe the issue was gummed up piston rings and the Seafoam additive managed to loosen them up. So to sum up, $12 can of the additive fixed this car.
