Engine Funny Noise problems of the 2011 Infiniti EX35

This car had an unexplained episode of sudden engine power loss and deceleration followed by engine shutdown and temporary inability to restart the engine. While traveling at approximately 60 mph on a slightly inclined highway, I suddenly felt that the car needed to downshift but it was not doing so. As I continued to exert additional pressure on the accelerator, the car began to noticeably and quickly lose engine power. The power steering and power brakes worked normally, and I was able to pull off the road, by which time the engine had stopped running. I estimate I traveled approximately one half mile from the first sign of trouble. There were no unusual sounds or odors. If any warning lights came on, I did not notice them. Accessory items such as the radio, air conditioning, navigation system, and power windows still operated. I tried several times unsuccessfully to restart the car. The engine did not turn over. I did not notice any unusual lights or messages on the dashboard, but the brake pedal did not depress as it normally does during the starting process. The tow truck driver who arrived a little more than an hour later started the car normally. There was no hesitation in starting, and the engine ran smoothly. The incident occurred about 10 to 15 minutes after I started the car for the first time that day. It had been driven less than 5 miles in the previous 5 days, but otherwise there was nothing unusual about the driving conditions. Since this incident, the car has been driven about 700 miles on the highway and been used for several days of local short trips without any problem. It has been checked at a general purpose auto repair facility and then by an Infiniti dealer. Nobody has found anything to indicate what the problem was.