When the car gets hot operation temp. and then shut it off to run in the store or whatever, come back and try to start it it will just clik.It did that a few times I held the key all the way to the run ..and then wiggled the key and then it starts.
I think that there is somrthing wrong with the igintion.I just changed the starter,with a Bosch rebuild.

 

is it an auto?

 

Manaual

 

maybe yoru ignition barrel has bad contacts like every other electrical connection with this car..

 

Could be a corroded battery cable. Sometimes the cable corrodes under the sheathing. Try bending the negative battery cable and break up some of the oxidation. If that works, buy a new one. Other than that, it could be a hundred other rusted, temp-baked, connections.