Rig up a wire to check voltage at 2 places and monitor the voltage while doing the things that make the car stop running:
- The 12V feed into the ignition module
- The 12 IGN supply into the ballast
All the actions that cause problems will drop the voltage some normally , but I suspect that there is wiring problem that is causing a big voltage drop at either of these supply points to the ignition system. Find what is going on at those 2 points and let us know.
Also, measure the ballast resistance; it needs to be under 1 ohm cold. The original was 0.5 to 0.6 ohms cold. If it is higher, then you have the wrong ballast.
We recently found where someone had wired IGN1 and IGN 2 wrong and the field current was going through the ballast! So wiring muckups happen...