I've been having the same problem. Both with and without hijack. My player is directly connected to my battery (with inline fuse), but only happens when I am say pulling up to a light and my RPM's drop. So I'm pretty sure it's my battery. It could use replacing either way. When is it happening while driving? Is it always under the same circumstances?
_________________________
-Michael

#040103696 on a shelf
Mk2a - 90 GB - Red - Illuminated buttons