hey bro thisll sound dumb, but my buddy and I were having the same issue on his pontoon boat, if we turned the stereo up above a certain level itdd cut out and come back on. We tried running a dedicated positive, and it helped a lil, but what ended up fixing it was when we ended up abandoning the stock like 20 gauge ground wire and ran a 12 gauge ground right to a bolt on the frame of the boat to the headunit and voila, works perfectly solved the prob. try that, run a wire directly from the positive on the battery to the head unit and see if that works, and if not try grounding it directly by using a larger gauge wire to the battery and which ever of the 2 fix the issue, run a dedicated wire and itll be good.