Recently, after exiting the freeway, may car ( lexus 1995 SC400) suddenly stalls. After a moment of panic, i placed the emergency blinkers on,. coasted to a stop, and re started the engine. It started right away and I continued driving home. The engine sounded perfectly fine, no hesitation, no roughness. After a few days it happened again....again after exiting the freeway and slowing down for city traffic. The Garage that serviced my car for many years has checked the electrical system, replaced the spark plug wire set, cleaned " throttle body". These seemed to fix the problem. The car was fine for 6 months and then it happened again last week. Need help quickly as this is making driving a stressful and fretful experience.