96 LeSabre dies after driving 5 miles then it wont start till it cools down

I have a 1996 Buick LeSabre.
It start and runs fine, it sounds good, it also
drives good.  But it will only drive for 5 to 15
miles, and then it dies, and it wont start
again until it cools down. We have had all
sorts of things replaced by our mechanic,
like 10 different things. I don't have a list of
them right now. Bit I feel like the heat is
causing it to die and that it is a wiring issue.
Has anybody experienced this? I have
searched through this site but they don't
have to wait to start the car and the dying is
more sporadic. Does anybody have any
thoughts or leads? I would really appreciate
the help, we have spent way too much
money on it and we might have to just let the
mechanic just keep the car for payment for
work done. Thank you very much.