hifonics brutus.

Why does my amp play randomly and when i tap on it or when i hit a bump my amp makes my sub thump what can it be?

I was playing music not even loud then all of a sudden my bass cut off i checked my amp and it still had power and my fuses are not blown but if i play music you could feel the sub playing but doesnt play normal as it should u could just feel it playing even tho i put the gain up and i took my...

So Im lookin at gettin a 97 z71 and puttin a 15" level 4 DC audio in it with a hifonics brutus 2.0k or whatever powerin it. Any thoughts on that? And it's a ext cab, I want to be able to still carry a person back there so the box can only use up to half the ext cab area. I need help on a box...