Check out this article: http://www.calgaryfieros.com/OSGdocs/code42.html
If you had a code 42 this may be the problem. I had a similar experience and the check engine light didn't come on until the second occurence. I was ready to change the ignition module until I read the article and started checking the plug wires.
On mine it turned out to be the #4 plug wire rubbing against the intake manifold. There is a sharp edge on the corner of the manifold and it had partially worn through the split wire loom that's over the plug wire at that location. There was no damage to the plug wire (silicone) but there were pin holes in the loom where the spark had arced through. I bent the plug wire guide down to increase the clearance, replaced the split loom and the problem went away.
(edit for spelling)
[This message has been edited by spark1 (edited 02-24-2004).]