Although the computer should usually be replaced as a last resort, it appears that you are about there. I feel your frustration. I went through the same thing on my 96 mini-van and replacing the computer with a junk yard unit resolved the problem (now about 7-8 years later with no no-start problems). It could be a bad solder joint or hairline crack on a board inside the ECU. These are sealed and potted, so no troubleshooting is possible.
You may not find one in a local boneyard, but check E-Bay. There are lots of yards that have listings on EBay. Also, there are re-manufactured units out there (A1 Cordone), and I remember seeing prices shown at about $100+.
Anyway you look at it, it's a gamble, but when you have exhausted all the testing possibilities, you've got to try the last resort.
Back in another lifetime, I owned a 91 Sundance and a 91 Spirit (still drive that one everyday). I had a computer failure that was the internal voltage regulator. The computers were identical so I could swap them for troubleshooting purposes. Man, that sure was nice.
Don't give up yet! Once you get to the bottom of it and get it fixed, you should be good for many years to come.
Best of luck and keep us posted.
You may not find one in a local boneyard, but check E-Bay. There are lots of yards that have listings on EBay. Also, there are re-manufactured units out there (A1 Cordone), and I remember seeing prices shown at about $100+.
Anyway you look at it, it's a gamble, but when you have exhausted all the testing possibilities, you've got to try the last resort.
Back in another lifetime, I owned a 91 Sundance and a 91 Spirit (still drive that one everyday). I had a computer failure that was the internal voltage regulator. The computers were identical so I could swap them for troubleshooting purposes. Man, that sure was nice.
Don't give up yet! Once you get to the bottom of it and get it fixed, you should be good for many years to come.
Best of luck and keep us posted.