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It's worth checking the wiring connector that plugs into the coil. Also check the wires that run from the coil to the DS2 box, that whole harness. I had a loose wire at the coil once and it caused my truck to run horribly. It was where an old wire splice had broken loose over the years.
I swapped in another coil harness and it fixed the problem completely. (Swapping the harness is easy, it just unplugs; alternatively you could just repair your existing harness.)
FWIW I have an old Motorcraft DS2 module with at least 75% of the epoxy melted out, and it still works fine...LOL
When you talk about the coil harness, are you talking about the plastic coil connector that clips on to the coil? Or are you talking about all the wiring between the module and the coil?