I just purchased a 2010 fj. The book says change the oil at 5k, with the 0W 20 fully synthetic oil. That seems very excessive. I would think 10k would suffice. Then I read on the forum that people with 2010 FJs get something in the mail that says 10k miles, and that the maintenance book in the glove box is incorrect? Can someone please comment on the correct frequency? Thanks.