I have had two 8" kickers running off of a 400 watt rocksford amp. I have always played them loud. Until recently they have faded and came back and the amp isnt over heating all wiring seems intact. i have ran this set up for a year and only now am i having a problem. i have gone on 11 hour drives with 0 problems. but now within 1 minute of the sterio turned up they kick off for about 5 min and come back for 10 seconds then kick for another 5 minutes. If any one has suggestions please let me know.