s-10 shuts off while driving

My 96 s-10 blazer, automatic transmission, v-6, will shut off while driving. It has happened while on the throttle and while off. On 3 occasions it lost power (dash lights went out or abs light blinked on and off) then the power came back. All other occasions it just shuts off and you have to restart it. It has no problem restarting. It doesn't run rough before this happens and gives no indication it is going to shut off.

Any ideas?

could be the ignition switch not the key cylinder but the black box below the key cylinder it is in the steering column many posts on it usally it fails when you try to start but will cause a stall the key is no dash lights but everyting else electricall works radio etc part is about 40.00 or so just had mine done 97 blazer