A new Recall just came out from Nissan for a faulty Ingnition switch relay
most vehicles Produced from Aug 2003 to July 2006 are affected, including the Xterra models.
http://www.wpri.com/dpps/money/auto_new ... gr_3633525
It says that the vehicles could stall, but as of yet no accidents have occured from it.
Check with your local dealers to see if your vehicle is effected.

Thanks, Ernie. I'll have to set up a visit to see JT!