Mopar performance elect ignition

After sitting always start with making sure of good grounds on the ECU.
Check, clean, tighten the distributor pigtail connector.
Check for power at the coil in the run and start positions both of the key.
There is an ECU test that is easy, by touching the exposed terminal of the distributor connector on the ECU side to ground.
One touch and release of that pin to ground should be one spark from the coil. (with the key on)

That ought to get you started finding the problem.