okay i got a 4 guage wire going into a tsunami splitter which splits it into 8 gauge wires.. one goes into a clarion dpx1001.1 and other into a apx640.4, the dpx is hooked to a sub, apx is hooked to speakers. When im driving and car is in neutral, or stopped, it works fine, wen i put it into gear, the speakres go off, sub still works tho. I switched all the power wires from the dpx into the apx, same problem. People said it was the ground, so i re-did the grounding, same problem. Is the amp messed up ? i put a test lighter, power is always going to the amp, yet the light for power always goes on and off...
Does the problem occur reguardless of the volume level? Have you tried disconnecting the dpx entirely? Just have apx running. See if it works. If not, then it could be that amp. Normally when an amp cuts out, it's due to lack of power/current flow. You could have 12v but if it doesn't get the needed current then it'll shut down.