I have had an AVIC-Z2 with a JL 500/5 installed in a 06 Tacoma for about 6 months now problem free. Just in the last few days I'll be driving listening to tunes and the volume will just about cut in half. When the volume get lower like it has been ill pull over and leave my truck running and go back to my amp and jiggle some wires to see if I can find a loose one. I cant and for that matter Im not even positive its the amp that causing it. For the past 3 days every time Ive gone for a drive it done this about 10-20 mins into it. I have a JL 500/5 with 2 focal 6.5 components in the front and 6x9 rear. I have a really short ground cable to my amp (2 gauge) and I grinded the paint down around the area where the amps grounded to get a good contact. I have tried different ground locations too while the problem is happening but no luck. The wierd thing is I dont think it a wiring thing. Thats why I wanted to ask here. Im trying to figure out if it the AVIC or my 500/5. I also have a sub gain knob that is run from the amp to my dash so I can control sub level. When the volume cuts in half I also loose any conrtol of my sub from that knob. The sub does still play but its very low. And when the volume cuts in half I can still turn it up using the AVIC vol + but the sound quality is just garbage. It just sound alot worse compared to before the volume cuts down. I dont really have another amp to try but If any one has expirenced anything like this with their AVIC please let me know. Now when I drive I get about 10 mins of listening before it sounds like crap. I have done the firmware update, and my AVICZ2 was one that was having issue booting up but firmware fixed it. Thanks in advance.. -Brian