check engine light is on, idle is very high, abrupt shut down when van is turned off?

Your vehicle is in "limp in" mode. You may have mechanical error with one of your sensors ... bring your vehicle in to a repair facility and have the codes pulled to see exactly which sensor or item is faulty.

Did you find out from the dealer what the problem was with your van? I have a 2004 Freestar with a 4.2 engine that is doing the EXACT same thing. Any help would be appreciated!

yes it was MAF sensor and IAC valve motor issue.