1992 Dodge Dakota Truck dies while in motion

I recently bought a 1992 Dodge Dakota truck with a rebuilt Katrina title. Everything seems to run fine, no check engine light on, but the truck will die sporatically. Sometimes it restarts immediately, but sometimes it takes up to an hour to restart. Check engine light will not light up when it's dead. All other electrical equipment seems to function when dead. Only codes thrown are 12 and 55 for end of test. It skips #88 for start of test. When truck re-lights, check engine light comes on and functions normally. When it dies, check engine light does not come on at all. Power source to computer has been tested and is receiving power when truck is dead. I suspect this is a computer problem and the computer needs to be replaced, but I'm not sure. Do you have any suggestions?