Jeep Cherokee Stalling

I have a 1998 Jeep Cherokee with the 4.0l inline 6 and automatic transmission. It has 115000 miles on it but is in great mechanical conditon (60k highway miles). Recently it started "stalling". As you run down the road at any speed the engine seems to loose all spark. The gages fall towards their off position (fuel, tach, volt, speed). Then about 1/2 a second later power seems to come back and you get a 60 mph rolling start with a jerk. The check engine light flashes but does not stay on. I don't have a code reader but I believe it is not showing any codes. It will do this at any speed and when stopped it will stall. After some cranking it will start and run fine. It acts like a dead short somewhere. I have replaced the enigne control computer with one from a junk yard and get the same behavior. The radio continues to run the whole time so it appears there is power. I don't want to replace multiple items and find the problem by luck. I'm not sure what could cause this behavior. Since it does this cold or hot and restarts fairly easily I dont suspect the ignition module. This model does not appear to have an external to the tank fuel filter so I have not changed this. I wonder if it could have a failing ignition switch or if the main ground or an alternator ground could be the culprit. The batery is fairly new and connections are good. Any ideas?