OK well after you have confirmed that the ASD is good, you should check your grounds, as well as power to the coil. Also, these may be stupid questions, but how did you determine that you have no/intermittent spark? Did you use the whole screw driver in the sparkplug trick, and if so are you sure that you had the screwdriver close enough to the block of the engine? Did you test the wire coming out of the coil, or one of the sparkplug wires? If you have spark coming out of the coil, but not out of the sparkplug wires, you may have a bad distributor.
Basically I would grab a voltimeter and starting at the spark plug wires, trace all the way back until you find power. You can bet that the junction/fuse/relay/whatever which is distal to where you locate your power is being lost. Other suggestions such as crank sensor and such are also good ideas.