There could b allot of factors involving this problem first could and most important is to make sure theres no loose connections in your wiring and find out how ur subs are wired in. are they SVC or DVC (single and duel voice coils) also what are theyre impedences if SVC could be 2, 4, or 8 also the same as DVC but jus 2 sets of terminals. find out first then the reason i ask is cause allot of half way manufactures are installing a device u could say that will cause amps to automatically cut off when the load on the amp reaches its lowest impedence load so when ur subs are moving in and out that load varies with how far the sub is extending out jus cause a sub say its a 4 ohm SVC doesnt mean that when its pounding away the load may actually be 3 ohm when fully extended. find out these variables first and then reply and ill let u know what to do properly.

Check all your wiring and make sure everythings connected right.