Your 1998 ford windstar starts up fine but then stalls unless you rev the engine for a little while but once its running it runs fine until the next time you go to start it any ideas why?

1) fouled spark plugs

2) fuel mixture problem (as from vacuum leak or some such thing) requires O2S feedback to compensate

3) bad IAC, can't move to high-idle position. When engine warms up, desired IAC position closer to stuck position

If your check engine light is on, consider if any stored codes relate to any of the above.