Take the coil pack off of the ign module by removing torx screws and unplugging spade wire connections underneath (remember where the wires go!). Check resistance across the bottom connectors, should be <1 Ohm for paired connections (across from each other), and open circuit to unpaired connections. On HV side you should get ~12-13 kOhm for pairs and open circuit everywhere else. Also should be open circuit from HV side to input voltage side. If this all looks good, its probably ign module, or connector, or (???), although coil packs can have intermittent operational problems and still cold test ok (i don't think this is common).
Caspers also has a slick ignition spark tester that allows you to test the system under load and figure out if and where it is bad - $120. Other people will have to comment on its usefulness.
if your module is bad you might consider Type II ignition module switch. Parts are in the junkyard - coils are everywhere and have advantage of being modular pairs rather than all coils in one pack.
i recently tested mine because 2-5 cylinders getting no spark. swapping wires showed me the coil pack was ok, but ign module not sending low voltage to coil pack. coil pack tested ok with above test. now i'm looking for a Type II ign module.
