I had a similar issue with mine, it would run like poo sometimes and other times it would run awesome, if you stopped at a set of lights it would sometimes just turn itself off, replaced the AFM and no problems after that. Then it came back again, but it was a bit different because it usually happened when driving at night time we could notice the lights dimming, turned out to be one of the amps powering a sub, removed it all and ran a 12" on a smaller amp and it was fine.