When u go to start and it won't, does it turn and sound starved of fuel? - check fueling.
does it just go dead (electrical)- if so does it behave better in the cold or hot? If it goes better in the cold could the heat be expanding soemting and disconnecting it, break in a circuit, wires etc...
Or do u have a immobiliser? Get it disconnected, I would try it first, they all can fail.