My windstar was running pretty good after taking care of my check engine light ( about a month ago). Yesterday while on the freeway it suddenly sounded as if the engine was revviny up and the vehicle was slowing down.It seems that I had to really push the gas pedal very hard to make the van move. At the same time when I was taking off from a light, it seemed as if it could not go into the overdrive gear. I finally got help and got it pushed for almost 60 miles for fear of ruining the tranny.I sure could use some help from you good folks.

OK I know someone out there can help me on this matter. I turn the engine on when cold and the engine seems to run fine , even with the check engine light on. As soon as I put the van in gear, it seems to run fine. When I try to pick up speed it jerks and the engine seems to just rev up and it sounds like a vehicle sounds when it struggles to go into the passing gear. Any ideas? Anyone?

How many miles on the trans? Do you know what the CEL/DTC was from before.. Is there any noise with the slip?

About 130k. The cel before was due to #4 cylinder misfire. I cleaned out the fuel injectors and swapped two of them to make sure the one which came from 4 was not bad. Replaced the upper intake gaskets. Also replaced thermostat as well as temperature sensors. The noise it makes is like a loud winding noise.
This cleared up the cel long enough to get it inspected legally.

Try changing the fluid, if its low, or burnt it could cause sliping, if not there are a few other things like the torqe converter...

my 98 windstar began suddenly downshifting at highway speed. Replacing the transmissionneutral safety switch solved my problem. It does more than prevent starting in gear.

Was the tranny slipping out of OD? My 99 won't go into OD anymore. Everything else is fine.