Hi, firstly i am very new to this forum, Im not sure if this is going to help however, i have a Corolla 2002 hatch zze122r 1zzfe im currently running the Pioneer 308D4SB 12" Sub 400rms Pioneer Amplifier GM-6400F I have 3 child anchors in my boot 1 for each seat, im using the far left one and it has been a great connection for me, My positive is ran through the grommet near the firewall and directly to the battery. Try the child anchor, also clean the terminals and make sure everything is on tight, amp connections too. Im sorry if this post didnt help
