If you are using the "1st Gen" 70-200mm f/2.8 VR (as opposed to the VR II model), then you might have one that is getting stuck. I have a 1st Gen 70-200mm f/2.8 VR, and mine suddenly stopped auto-focusing. I figured out that it would get stuck when at one end of the focusing range. When it is attempting to focus, it would go to one end of its range, then try to go back the other way, but it would get stuck when it would hit the stop on the end of the range. Then it just would not focus in the other direction unless I reached up and moved the focus ring manually, thus "unsticking" it from its trapped position. Then it would auto-focus just fine for a few shots, but if it hit that stop at the end of the range, it would stick again. I am probably going to have to send it in to a Nikon service center to have it cleaned and serviced if I want it to return to normal functionality.
- TBonz likes this