Please read the sticky at the top of the Blue Oval Lounge.
Not trying to be rude, but this belongs in the Windsor Power Forum. Thanks.
Having said that, yeah, this is weird!
I would double-check your connections @ the Duraspark module, and be SURE the grounds are EXCELLENT! Otherwise, it's just pulling too much current and will cause failure such as this. I can't stress that enough, as I have first-hand experience in the older Fox-bodies losing ground connections.
After that, I would look at the
ballast resistor wire that's in the dashboard (behind the instrument cluster). If that wire has burns or is shorting to ground, it'll cause ignition problems up the ying-yang; I've been in this situation, too! To identify this wire, it's a typically LONG-ARSE wire, red in color (as far as I have seen), and usually has the words, "RESISTOR WIRE" or something similar printed upon it in silver or black ink. I've pinched this wire between the steering wheel support brackets before, and it was pretty cool having a fireworks display with smoke right in front of me.
One way to verify this type of problem is to check for battery voltage AT THE MODULE
AND THE '+' SIDE OF THE COIL, whilst the ignition switch is in the "RUN" position. I assume you have a pinout of the Duraspark module, so you'll know where to check, right? Okay, moving on.....
The only other possibility I can come up with off the cuff is that maybe the ignition switch (NOT the cylinder) has problems. They've started more than a few Fords on fire.