1993 Nissan Quest GXE.

Twice while my family and I were traveling in the high country (Yosemite)
and after a few hours of driving sometimes at around 65mph or more, we begin
to descend from the mountain peak. Suddenly and without warning, the car
feels heavy and pressing the acceleration peddle does nothing. A few seconds
later the ignition and other indicators light up on the dash board. The car
has stalled. No brakes, no steering and in most cases, no place to park.
Once we finally parked the car in a safe place, we begin inspecting the
vehicle. Coolant looks fine, oil is good, electrical looks fine, etc. I
remove the air filter to inspect and it looks fine. After a few minutes of
allowing the car to cool, I start it back up, and the problem appears to
disappear for a few years! Yes years.

Does anyone know if these cars have problems with the combination of
altitude & heat? As this may not seem like that severe of a problem, it puts
us in extremely dangerous conditions. Usually when the car is brought in,
the techs end up not finding the problem and charging me for other stuff
unrelated.

Thanks,

Roy