I have a 1990 Nissan Sentra 5 speed. The battery is new and the posts are clean and tight. Every so often when you turn the key nothing. No juice at all. If you play around with clutch, key in ignition, or gear shift it regains power and starts. I have no idea what makes it start. I figure it must be a problem with the ignition system, but I'm unsure what to check. Any suggestions?

check all the wires to make sure they're solid (battery ground, alt to batt cable, etc)

maybe its the starter...