You can read more about it here and listen to the podcast. The story involving the man in white is near the end of the podcast.
Here’s the summary:
The caller said she and her husband were driving up a mountain in Utah a few years back in their ’89 Toyota Camry (which they implied was pretty old at the time). Their car stopped on a remote road near the top of a mountain. The tried “a hundred times” to start the car, and the husband, who had worked in an auto shop, tried to see what was wrong. They couldn’t figure it out and thought they would have to spend the night in that remote spot.