Starting Problem

1998 3000gt Base Model. Starter Rebuilt,ignition Switch Replaced 2x, Wiring Harness Replaced 2x. Frequently The Car Won't Turn Over Until It Is Tried Several Times. The Only Sound Is A Small Click Until It Finally Turns Over. I Printed Out Several Forum Suggestions. Does Anyone Have Any Good Pointers ??????????? They Would Really Appreciated As It's My Wifes Car.
Thanks