1999 Ford Windstar dies then will not crack unless jumped off
 

1999 Ford Windstar 3.8L 112,000 miles on it. While driving, the power steering pump froze up. I replaced it and got it working fine. The next day, I was test driving it and came to a stop light. The van idled really rough then died. I was able to crank it immediately and though the engine would surge (almost like a vacuum leak) I was able to get it to my driveway. While turning around in my driveway, I applied the brakes to make the sharp turn and the van died again. I attempted to crank it again and the starter would clunk (not click, clunk, almost like the starter was hitting he flywheel.) I tested the battery and it reads at 12.5 volts. I attempted to jump it off with no change. I bought and replaced the starter. I was able to get the windstar to crank with the new starter and it ran smooth after cleaning out the IAC. While letting the van idle for about 15 minutes, i drove around the front yard and slammed on the brakes and making sharp turns, and the van died again. Once again when I attempt to restart the van and the brand new starter makes the same clunking noise.

At this point, I have checked the serpentine belt, it is almost new and lined up perfectly, new battery, new starter, alternator is less than a year old, IAC sensor has been cleaned and the rod moves easily. At this point I need some suggestions. And maybe a little luck.

It might be a good idea to check the flywheel flex plate. Sounds like it's moving around.

Update
 

So I let the van sit over night. I went out this morning and it was able to crank the van under its own power without jumping it off. At this point, the motor has developed a knock. Sound a lot like this link
Oil is full and fine. Van has never ran hot, and I do not believe that it is the actual motor knocking. Anyone had this one before?

Link to the video of my actual van. Hanky, you said it might be the flywheel flex plate....If so, how do I check that? I am a newbie, and I am trying to get this van fixed so I can get my dad to his doctor appointments. I apologize, if i'm being redundant with these posts, but it seems like every time we fix one thing another problem pops up. Thanks again for all the help.

There should be a cover on the lower section of the trans where it attaches to the engine. If you remove the cover you should be able to see the flywheel. Cracked flexplates were a common problem with those vehicles. Consider having someone at least look at your vehicle for that problem. If it is confirmed it will possibly require an updated part to prevent a recurring problem.
Our Ford parts expert,Kyle, might be able to shed additional light on the problem and the measures needed to correct.
I have also heard vibration dampers produce a similar noise when the rubber cushioning gave out.

Thank you Hanky! The flex plate for this vehicle is obsolete if you we interested in buying OEM. DelBalso Ford (PH: (570) 288-4501) shows to have one of them in stock, part number XF2Z-6375-AA. I would have the vehicle looked at before your throw any more money at it because that knock sounds awful.