Subwoofer Amps Shut Off?

I have a 06 Acura TSX w/ stock alternator and battery. Headunit is factory and amps run off speaker level inputs. All car speakers (four 6" and two 6x9) are Alpine Type-R. I have two Alpine 12" Type-R subs. These are 4+4ohm DVC models that I have wired for 2 ohms, each powered by its own Alpine MRP-M450 amp. Amps are 2 ohm stable at 400 watts. An Alpine MRP-F450 feeds all 6 speakers. Two seperare 4ga wires power a 1 farad (speaker amp) and 5 farad cap (both sub amps). The two caps negative leads are run together into a distribution block that outputs one 4 ga ground. The remote turn on is run serially left sub amp to speaker amp to right sub amp. System is 3 months old. When listening to music, my sub amps will turn on and off but my speakers will not. Speakers have never cut off. Both sub amps will turn on and off together. Amps do not have a fault light. I have rewired grounds and recharged caps. Voltages are over 14. Gain is +0.5V, B is +1db @ amps, -2 @ head.