You may have a worn rubber bushing on the shift cable end. Check out this thread for what happened to me. You may be at the beginning stages of the same thing.

http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=tranny&Number=1016661&page=&view=&sb=5&o=&fpart=1&vc=1

Jim Johnson 98 SVT 03 Escape Limited