Matt,
More than likely your ignition relay,emergency ON/OFF relay or EFI relay has gone bad or is intermittent.
Typically speaking a voltage difference between pin 85 and 86 on a relay will cause the relay to open or close (depending on the type of the relay). That means that when the relay is energized there will be contact between pin 87 and 30. If your relay has a pin 87a, when the relay is not energized pin 30 will be connected to pin 87a.
A good relay should have very little resistance between pin 30 and 87 when energized. If your relay has a quenching diode inside to prevent a voltage spike when voltage differential is removed from pins 86 and 85 the polarity of the wires to pins 86 and 85 is important. The striped end of the diode should be connected to the positive terminal. On the housing of most relays there is a drawing showing where the ends of diode are connected to. The diode is designated by a rectangle with a vertical line on one of its vertices parallel to the opposite side. Positive voltage should be applied to the terminal that is connected to that end of the diode with the vertical line (cathode). If the polarity is reversed, then the diode will be shorted and damaged. If your relay ONLY has a resistor then you can connect pins 85 and 86 to a differential 12 volt without having to worry about polarity.
To check a relay, removed it from its housing. On the bench, connect pins 86 and 85 correctly to the battery (check polarity in case there is a diode in your relay) then measure the resistance with a voltmeter between pin 30 and 87. As you connect and disconnect the battery connection to terminals 85 or 86 watch the resistance between pins 30 and 87. You should be getting a REPEATABLE resistance of approximately 0.1 ohms. If you are getting above 1 ohms or the resistance fluctuates, you have a bad relay.
If you need more info on relays, go to the following web site and on the menu on the right go down to item 36 that is relay. Click on the relay link and you can then read all that you need to know about how a relay works.
http://www.bcae1.com/
I had a similar problem to yours but to make the matters worse it was intermittent. It took me a while to figure out what was going on, because my problem was not repeatable. In my case the coil/fuel pump relay had a resistance of about 70-80 ohms (occasionally). In some cases, I could hear the fuel pump energize but the coils were not firing. When I was hitting the starter, the engine was turning and turning but with no spark. For the heck of it I opened the relay and looked at the contacts. I had arcing between the contacts. Just picture in your mind trying to align two cones with the sharp tips against each other. Some times only the points were contacting each other and some times the sides of the cones. I sanded down the contacts and the resistance went down to around 0.1 ohms. For the peace of mind I replaced the relay anyway. While you are at it, I think it will be a good idea to check all of your relays this way you know for SURE they are fine. You can then eliminate them from your list of suspects.
If you have a bad relay, I do recommend you replace all of your relays. They are of the same age and have similar number of hours of usage. I had a second relay go bad within two months after the first relay went bad.
Also note that in some cases a bad battery or dirty/corroded battery terminals can manifest themselves with similar symptoms.
-Fariborz