Engine turns off after driving at above 65mph for over 1 hrs. and slowing down on 1996 Lexus LS400

Low milage always garaged 96 Lexus LS400. When we drive the car for over 1 hour on the freeway at an avg speed of 65mph, then either you slow down for traffic or taking a exit, the motor turns off. No warning, very dangerous as the power steering and brakes obviously don't work easily. It's been to the Lexus Dealer shop twice, once for two weeks and they could not find anything wrong?

Asked by for the 1996 Lexus LS400
4 answers
Yikes, maybe you could have an ignition problem.
Possible fuel or ignition issue, would attempt diagnosis by driving with a fuel gauge attached and duplicate the scenario to turn the engine off.
seek diag from your mech it could be fuel or ign related
Were YOU able to duplicate the symptoms for the dealer since your 11/26 posting of the same question? IF they can't duplicate the problem , and there are no DTCs set , then most likely , they won't find a problem that doesn't exist while they have it.