I have a 2003 Ford windstar that keeps shutting off on me. I gave it a tune up, a new alternater and a new battery and its still shutting off. I would take it to auto zone to get it checked out but it shuts off on me while I'm waiting for the light to change. Can u please tell me what's wrong with it.

SOURCE: 99 Taurus (DOHC) Dies when slowing down or idle.

try replacing the MAP sensor, if you have fuel injection. Your air/fuel mixture is bad.

SOURCE: 2003 ford explorer battery light on

Are you sure the alternator isnt "over" charging? if not, you may have a "loose" connection somewhere with the cables, or a malfunction in the dash cluster. Also, are you positive the battery is forsure good?

SOURCE: 2002 ford windstar states check charging system

voltage sensing circuit could have a problem, if the sensor is bad that senses the voltage coming from the alternator or battery it will set this warning off, follow the wires from the battery and alternator untill you find what looks like a little module or a clamp around either the negative or positive battery wire or alternator wire. see if the vehicle reacts when the module or sensor is moved around a bit

SOURCE: Ford 2003 Expedition EB. Check Charging System

Its probably the alternator. It will need to be tested on the vehicle with the engine running and the light illuminated. Measure the battery voltage with the engine running. It should be at least 13.5 volts. If it is lower have the alternator tested at a shop with a charging system tester.