I am experiencing an odd problem. Problem showed up suddenly without warning. When I am parked an in drive and push on the accelerator the car very slowly accelerates. It's like having a manual tranny and trying to start from a stop in 3rd gear. No tranny slippage. Overdrive causes the same problem. When I manually downshift to 1st the car accelerates with no problem. When I am up to speed I can return the car to drive and there are no problems. When I stop or slow down again, problem re appears. Any thoughts?

Time for a complete replacement of trans fluid and a new filter. If you search from the Taurus main page and use the search function, there are posted procedures for doing a total fluid drain and replacement. You can try this too.
http://www.taurusclub.com/wiki/index.php/How_to_Flush_your_transmission_at_home


Some recommend using Auto-Rx as a pretreatment to prepare the trans to be drained, helping to get all the junk out. It's only available at auto-rx.com, or something like that.

I checked the tranny fluid and it looks good, nice and pink, no burnt smell. Doesn't it change a darker colour when it needs to be changed?