Installed an alpine CDE-7870 in my Tercel. I have four speakers wired in and it works fine for like 15-20 mins, then the speakers just stop putting out sound. Head unit appears fine through display, can change from FM to CD etc. I thought it may be the use of existing speaker wire so I rewired everything from scratch except the power and gnd still come out of the existing chasis wiring. Can anyone help me? I am ready to stick a fork in my eye!