My 98 Windstar, just sold at 216K. Also the 3.8 mfg in Canada. Engine started to hesitate and I wanted a new vehicle. So I sold it a few weeks back. I didn't want to put any money into the van. Anyway, I had THAT problem twice, once about 123K and once near 196K.
Both time, I went to Pepboys and had the transmission flushed, and new filter, and the problem went away.
NOT TO SAY THAT THIS WILL SOLVE your problem, just advising what I did.
It was a great vehicle, only replaced the alternator about 103K, beside normal maintained.
Good luck!
a Canadian made 3.8. Coming home from the grocery store at 60 Km Hr/40 MPH
> it started shifting from high into second, then back up again, over and
> over. Today it did the same at first, then on the way home, this time at
> 40 Km Hr (different route) it was dropping in and out of overdrive,
> without any light, as the load varied. A few weeks ago, while going very