1989 E150 ignition problem

[blue.monkey]

I have a 1989 E150TXCEM. One of the cylinders has no spark. I swapped plugs and wires, and still the same cylinder with no spark. I use an external device to check for electricity, it seems to work well. I replaced the coil, and still no spark. I cleaned the low and high V terminals and made sure the were secure. With the engine running and the spark tester in place I wiggled the low side wire around pretty good to look for an open. Can the problem be the power pack that only affects one cylinder? Or should I cut back that wire and solder/heatshrink another in its place?

thanks,
Kevin