2003 Dodge Caravan What keeps knocking my computer out?

I have replaced my computer 4 times in 3 months. I have replaced coil, wires, plugs, crankshaft sensor, camshaft sensor. Van originally died at red light. Second computer lasted about a week. Third and fourth computer shorts out after plugging in. I usually get error code p0203 or p0303. Van runs but very badly. Took to dealer he said new computer and run a new wire to fuel injector number 3. I replaced computer and this one shorted out also. What is knocking out the computers?