Amp question, keeps cutting out

I have a JL Audio 300/2 and as soon as I turn it up near max volume, it cuts out, then bumps back up to full volume in two steps of volume increase. It plays there a bit, then cuts back out and steps back up. Any thoughts as to what may be causing this? I have adjusted the gain and I only get it to stop doing this with the gain way down and not much volume. The deck is a stock Clarion XMD3.

Thanks for the suggestions.

I have 2 jl amps in my boat and had the same problem in the beginning. the only reason the amp will cut out from what I understand is if the voltage drops to low. It was happening to me because to small of wire was installed for how far the wire had to run. The installer that originally did it used 4ga. I tore it all out and replaced it with 1ga. Problem solved.

Try adding a second battery solely for the audio system, but remember! To produce power, you need power! I had same problem in the audio system of my suburban, I added two batteries, one capacitor and upgraded the alternator now it rocking 3500 watts of pure devastation.... Huh .........what did you say?

Almost forgot the gauge of the power wire needs to be adecuate like tlb said. Try a 4 gauge or 0 GA. good luck

Thanks for the input, I will make some changes and see what happens.