2000 XK8 Starting Problem

Hi, My 2000 XK8 has a strange starting problem, when I turn the key I get a hiss sound coming from next to the passenger side fuse box and everything goes dead. If I disconnect the Battery and then connect it again everything is fine and it starts? John in BC Canada

Check the hot wire to that fuse box is tight and also the ground point. The hissing you hear may just be sparking.