Nikon 18-55mm lens attempts to auto-focus but continues to go back and forth?

I have a Nikon Af-s 18-55mm lens that I have tried on multiple cameras, and all experience the same problem. It used to work fine where I would hold the shutter release button half way down, the lens would focus, then press the rest of the way to take the picture. At some point the lens started acting up. Now when I press the button, the lens continues to go back and forth as if it can't determine when the picture is clear.

At first I thought it must be the sensor in the camera, but the camera works fine with other af-s lenses. The lens still works in manual focus, and everything with the camera works perfect with any other lens.

Any ideas of what the problem may be or solutions?

Added (1). To answer your questions: the lens used to focus correctly on everything, indoors and outdoors, and now does not focus on anything. This happens with my d40, d5100, and d90. I was just hoping for an easy fix, but it sounds like it might just be the end of it's life.

There are also electronics in the lens. Apparently something has gone wrong there. Contact Nikon.

Are you testing this indoors? It's common especially with "kit" lenses that they don't have large apertures and so don't focus as easily when used indoors due to lack of light. There may be some sort of focusing assist built into the camera that may help, so it's useful to look through the camera menus.

If it will focus properly outdoors then it's almost certainly down to the above. Common issue, most apparent with cheaper and kit lenses, and on camera models at the lower end of the price range.

I guess I should ask, are you choosing a good target that puts the autofocus sensor on something with a good edge that it should be able to focus on?

It could be that the lens has gone bad. If it isn't under warranty, it might be time to ditch it for an upgrade like the 18-105mm, 16-85mm, or even something fancier.