motor shut down and loss of all eletric and power...?

[tturbonegro]

While driving the truck just shut down completly...like a cps failure...put it in neutral and it cranked right. back up...wts light came on immediatly, all radio stations were reset like the batterys had been unhooked..
The next morning it started once or twice normal then the third time nothing..no power to anything..no dash lights no nothing..checked battery terminals, gpr, starter wires, starter relay...jumped starter relay and it cranked.right.up...any ideas? Loose ground somewhere?
1995 250 xlt 7.3
Any help always appreciated, thanks!