88 D100 issues

My old dodge started running rough a week or so ago. It was pulsating and idling rough. After warm it got better. I had replaced the computer years ago with a used one when it was acting the same way. I unhooked the battery and reset it it. It ran great again however, the problem started up again. I odered a rebuilt computer and installed it. Truck ran worse. Put the old one back on. Now it wont start. Put the new one back on. Started but, ran bad. Tried to pull it in the garage and it died. Wont restart. Im thinking cam senser or crank senser. Truck is bone stock with 90,000 miles. The distributer has been replaced some years back. Same with plugs and wires when I had the first go round. Havnt checked for spark yet. Ran out of time yesterday. Any advice would be greatly appreciated. Thanks