My 96 XJ shut down. Like someone flipped a switch while waiting for a traffic light. Engine cranks but does not start. I have replaced the PCM (computer), distributor, rotor, CPS, distributor pick up coil and coil pack. Fuel pump is working and I have plenty of fuel pressure at the rail and the ASD relay is working. I am not getting a spark. Anyone have any suggestions as to what is going on?