I got a 2001 grand cherokee and when i get to a stop it turns off what could it be?

Needs engine tuning.

your idle air control valve is going out located behind the throttle body.

if the smoke is white could be a headgasket

This condition would be normal unelss you have a locking differential. Your description suggests that you do not.

There could be multiple things wrong there is a scan tool that can tell you what the problem is. Autozone does this service for free once they check it there will be a code to explain what is wrong.

Check your crankshaft position sensor

I would check the dealer for any TSBs

have the drivs shaft checked for a bad universal joint.

You need to turn the feature of last door closed. This located above the rear view mirror. Just push one the button that will lead you to the feature of last door open to be lock. Unlock and save the changes. It is also in your manual if you have them.

Check on Ebay for Jeep Grand Cherokee Harness Kit. The plug on your harness may be melted like mine was. I bought this kit, followed the instructions in his ad and it worked great. All I had to do was cut off my old plug and solder this one on. Even the wire colors matched so there was no guessing.