slight shake 2000 sel

this problem is new when i come to a stop there is a slight shake almost as if the van is going to turn off the rpm move abit not by much it had never turn off only once when trying to park.Does anyone know what can cause this or had the same problem. 47500 miles

On top of the upper intake manifold, next to the throttle body, is the Idle Air Control (IAC).
When your foot is not on the accelerator, this is what controls the idle speed. It gets a signal from the PCM (computer) and has a little motor that opens and closes a valve that controls air into the intake.

The IAC can stick.....and most of us remove it (just 2 little bolts) and spray some SeaFoam or WD-40 inside...to wash off and lubricate the threads that you can see in there.
If that does not work....it may need replacement.

Another thing that can cause your engine to stop.....when you have your foot off the accelerator....and are turning the wheels to manuver into a parking space..... is the Power Steering Pressure switch. This switch tells the PCM that the steering is working harder....and to boost the idle speed up slightly to compensate for it.

The first thing that I would do....is to clean the IAC...and see if that helps.