We had a 1FZFE that had a loose crank bolt.....well it was tight but not tight to spec. The truck had been to many shops....they would throw parts at it....never fixing the issue. The truck had intermittent power steering.......sometimes it would be there, sometimes it wouldn't. Very tricky to figure out. We torqued that crank bolt.....never had a problem again. And he had all new PS parts as a bonus!