How do you fix a 1995 Chevy Lumina 3.1 that will not start or even turn over but starts about one time every three hours?

It sounds like you have dirty/loose battery connections, a bad ground, loose ground wire on the engine block, loose hot wire at the starter, bad starter, or bad ignition switch.

I have a 95 Chevy lumina and i have rebuilt the starter, replaced the solenoid, put shims between the starter and transmission, changed the battery cable.