I was in italy when I had the same damn problem you did.
If I would bounce around in the cab and/or push the truck around violently from the roof rack then the damn thing would start. What the???
I had my vehicle hauled for $150 from the side of the road to the nearest english speaking guys shop. The guy laughed his ass off when I described everything to him. The english speaking mechanic popped the hood, took a wrench out of his back pocket and proceeded to torque down the clamp on the negative terminal. Then the damn thing turned over. I was so embarrassed. The dude didn't charge me for the 10 second job. Thank god... I took the vehicle home and took the terminal cables off and scrubbed the crap out of them with a brush and torqued the fu--ers down tight. No issues after that.
Initially the cables were on tight, but not tight enough; I guess. Now I always clean and check the terminals first when I have electricity problems.

2002 4dr Kia Sportage 4X4
Tires:235/75/15, Wheels: Black 15x8 Steel ProComp 2.5" B.S., Hubs:Warn Manual, Lift:3" UPYOURKIA, Trailer Hitch, Cargo Rack, Clinometer.