I had the same issue and it turned out that my front sway bar was cracked on both ends where the links go through it. Turn the wheels all the way to the right and take a look at the drivers side and you should be able to see the bar/endlink. Then do the same to the pass. side.
I would turn and get a dull thunk everytime that piece gave a bit, especially when backing out of a parking space and turning the wheel. It looked to be getting stuck on itself, then popping free at some point.
This is what I found on my drivers side...