Dies and restarts when cool is not quite enough information. But there are two very common temp related failures: FI system relay (formerly known as fuel pump relay) and the ignition power stage.

If it is the FI relay you can open up the relay tray, pull the cover off the relay. Turn off the radio and leave the fan on a nice quiet setting. When you hear the relay click, have a passenger push the contacts back together...On 760, this was usually enough to finish a drive in peace. In my case it was not the relay on my 1990 760 turbo but the relay socket but to the same effect...the heavy lugs could carry current but the coil would open and close intermittently.

If itis the power stage, about the only thing you can do in the middle of the desert is try to find new dielectric grease at parts store and re-grease the back until you can get the proper paste.