Do you have another ECU you can try? I have had a few go bad and they quit working pretty quickly. The first one I had go bad the car started to act up like it was missing a little when I was driving it. I got it home and shut it off. I tried to start the car and had a hard time getting it to start and when I did it would not idle on it own and sounded like it was really out of tune. After two times of starting and dieing the car would not start anymore. I swapped out the ECU and the car fired right up without any more problems.

The second one I had go bad was like a light switch. I had driven the car for a couple of years with the ECU box and after a drive one day I parked the car. A couple of days later I go out to the garage to start the car and it would not fire up. After some trouble shooting I figured out it was the ECU box. With the new ECU the car fired right up.

So given my past experiences I would try the ECU first. If that does not fix it then it sounds like it is the coil.