Im about to throw a fit!!! I have a Nikon D90 and just bought a lightly used nikon 70-200 thats 2 years old. For some reason it has a mind of its own on auto focusing. Sometimes it will actually search for a focus, beep and take a pic, and sometimes it wont budge. Ive tried turning it off and on, removing the lens, removing the battery and sd card. Ill take pics for a minute and then boom. No more auto focus. Ill fumble with it for 20 minutes and then boom, we have focus. Ive tried cleaning the little focus bumps on the lens itself but it did not help. The only thing i can think of is that it is not making good contact. If anyone has ideas I would gladly listen.