Amp keeps cutting out

I posted this a LONG time ago, but I recently got a new vehicle so I am revisiting my problem.

I just put my amp and subs into a new car, using a new box, new amp kit, and an aftermarket headunit. When I turn the amp up it cuts off. My amp is rated CEA at 900W RMS @ 2 ohms while my subs are rated @ 300W RMS @ 4ohms. I have them wired in series to two ohm load. Why would my amp be cutting out? Shouldn't the subs be distorting before the amps quits. Also, it shuts off for about 30 seconds and then turns on for about two minutes then cuts off again. I have to really pound the subs for about five or so minutes before it first starts. The gain on the amp is about half way up, the head unit volume is just over half I think with the sub out all the way up, and the remote boost on the amp is also at full. The subs sound great until it cuts.

Sorry wrong button...

Could the problem be that I am somehow still clipping the amp? If so, how? The subs are underrated for the amp IMO, there is no detected clipping until the amp just stops...

If my math is correct, since my subs are in series I still only need 300W RMS to drive them happily. If I did need 600W (Please explain why) I am still only using 2/3 of the RMS rating of the amp....

Shouldn't the subs blow before the amp senses anything wrong?

2 12" powerbass s-12 SVC

Kenwood KAC-9152D

Thanks for anyone's and everyone's help.

I am not sure of the voltage level, there is no guage in my instrument panel. I was driving down down the road doing roughly 50 MPH when it cut out. Why would the amp go into thermal protect though? I am not using the full potential of the amp (htat I can tell).

My whole problem is I had an American Bass amp rated at 1/4 of this amp that would play all day. Now I supposedly step up to a beefier amp that won't even play for twenty minutes before it wimps out.

If I were to set the gain properly I would only turn it down maybe 1/8 of a turn. I know the voltage of the outptus of the HU are 2.2 volts. I have the gain set roughly at 1.5 volts. The way I see it I should have plenty of amplifier headroom to be able to set the gain to wherever I want and the amp should blow the subs before the slightest hint of overheating takes place. Am I wrong in thinking this? Shouldn't an amp whose RMS is rated for over three times the RMS of the subs play all day?

There is no volt meter in my instrument cluster so I do not know the voltage before it cut out. I was doing about 50 MPH down the road when it started cutting out.

The amp shouldn't even come close to any type of overheating,clipping, or anything like that as far as I can tell. The amp's RMS is rated for three time the RMS of the subs. Is that not enough amplifier headroom?

If you search for posts I've made you can find the other threads I started.

I know the ground is good i took a dremel tool and ground all the paint off of one of the studs my seats bolts too. It is a brand new amp kit. No PAC part anymore. It is a Sony aftermarket HU I got from BestBuy. I don't believe it is a voltage problem because I know the voltage drops way below 12 volts even at half power because I have bass CD's I listen to and the bass notes play for ten minutes.

IMO I think this Kenwood amp is just not what it is cracked up to be.