Our dad has the same year Tundra, and the same engine. The truck has 97,000 miles on it right now. I'm a little surprised you have to add make-up oil. I try change the oil on his truck at roughly 5,000 mi.. He is a contractor, so he travels with his truck to different glass plant around the country. There have been a couple of times I change the oil after he came back after projects and it was 6,000 to 7,000, and the very longest was 8,000 mi.. I checked the oil level before changing it, and it was still at the full mark.
I was impressed, and attributed it to being a nice, tight and precise engine, with good piston sealing.
