drops dead

I have a 96 NG 900s that believe it or not from reading this group) has been a good car for me. 2.3 auto. 167k miles. For about the last six months Its been stalling out, but not always. It may do it 3 times in a day and then never do it again for 2 months! Some times at idle it will die..just hit key and it start right back up. Sometimes driving down the road at hiway speeds it just "drops dead" radio quits, SID quits, motor dies, but headlights and a few other things remain on. Again all I have to do is turn off Key and restart. Im thinking ignition switch???? Any help would be appreciated.