I had the crankshaft sensor go bad on my X trail , and it cut out at an intersection about 4-5 years ago on a particularly warm day. Fortunately I was able to pull over and check engine light came on. I was able to start it up a minute or so later. Drove fine for the rest of the day, but I was not going to have a repeat or have my wife stranded or worse, so I had the crank sensor change the next day.
The old style ones Nissan used had a plastic body shaped like a domino that over time would develop micro cracks and cause it to fail. The new ones have a conical metal cap. I have read a fair bit about the issue on different forums, and the original poster should change his asap, as its on the way out and will fail completely requiring the vehicle to be towed. Of course if it cuts out while you are trying to merge onto a highway it could be life threatening.