while i was palying some bass mechanik a little while ago doning some sine sweeps my voltage dropped from around 14v to 11.5. i did the big three. my alty is 130 amp. i have a autotek mm1000.1 and a kicker impulse 352 in my truck. is my alty going out or what would you suggest to keep my voltage constant? also this voltage is at idle, but goes back up to around 14v when i give it some gas. please help