Check your amp next time it cuts out, pull over and make sure its on and not in 'protective' mode. I have used a few amps and had similar problems I would replace the amp and all was fine again.
the setup I have now works no problem, but when I drove to Florida the last hour it stats to go to protective mode for a couple seconds. no idea I guess its tired after 8hours of driving... but I know thats the only time so no ground etc.. anyhow I believe its heat related don't know if its a problem your getting but like i say, just pull over when it dies and check it out, carry a multimeter around if need be so you can test power/ground is fine and amps running etc.
the setup I have now works no problem, but when I drove to Florida the last hour it stats to go to protective mode for a couple seconds. no idea I guess its tired after 8hours of driving... but I know thats the only time so no ground etc.. anyhow I believe its heat related don't know if its a problem your getting but like i say, just pull over when it dies and check it out, carry a multimeter around if need be so you can test power/ground is fine and amps running etc.