FI 4 life

NEED HELP! i have two 15" DC subs in a 4th order on a DD M2b at two ohms with a 100ah battery in rear and 14 volt stinger alternator under hood. when i press gas or turn gain too high amp goes into protect mode? in my old vehical i could run subs and amp on .7 ohms on 12 volts. ive done tried a new amp also and does same thing. please help