Power cap and amp won't stay on. (Help)

My power cap and amp won't stay on. At first I thought it was the ground, but I changed that to a better spot and it still won't stay on. It periodically pops on and I hear a single thump from my subs then thats it. It turns on when I start my car then turns off and turns again for a second when I turn off the car. Before it would turn on after I drive for awhile and stay on, but now nothing. Any suggestion to whats wrong with my system?
Comments
Do the rest of the lights in the car dim or anything while this is all going on?
I think you're seeing the on-off-on-off stuff happen because the system fires up, runs out of juice, waits for the cap to "charge", fires back up, discharges the cap, runs out of juice, turns off, etc. etc. etc.
How much current are you drawing, anyway? Do you even need the cap?
or anything that caused such an event
your radio will reset...