FYI, it *SEEMS* it was the cam sensor. We gave it a couple taps to
push it down a little more (after all, we were pulling on it trying to
pull it out) and so far the problem has not happened at all today. So
HOPEFULLY it was fixed.
As to why we changed the timing chain - it was rattling. Just as a
curiousity thing, I called Pep Boys and asked how much it would be and
they told me something around $500. This is on a first-generation
minivan.

Thanks everyone!
Eric Kotz