I hav a kenwood amp that puts out 900 watts rms and 1900 watts peak power.Does not get hot but tu?

I have a kenwood amp that puts out 900 watts rms at 2 ohms and 1900 max rating. On certain songs like put on by young jeezy the amp will cut off and cut back on continously during the song. I have 4 guage power and ground wire also a 2 farad capacitor. Have it wired at 2 ohms to two kicker cvrs that handle 420 watts rms each at 2 ohms. The amp never gets too hot but can get warm . It has a built in fan though. What could fix this problem ?