A version of this topic came up on the Nissan Frontier forum.
Those of you that purchased your R51 Pathfinder new did you notice your truck being sluggish during brake in? I purchased my truck used with about 7,000 miles and I noticed it would slow down quite rapidly when I would take my foot off the gas. That all changed when I hooked up my 5,000 pound travel trailer to my Pathy and drove it from Western MA to Cape Cod and back (several hundred miles) At that point I noticed my truck loosen up substantially.