1994 Chrysler Concorde HELP please!

Engine Mechanical problem
1994 Chrysler Concorde 6 cyl Two Wheel Drive Automatic

Okay our 94' chrysler concorde shuts up while drivng, we will be driving down the street and it just shuts off and then sometimes it will start up again and then sometimes it wont. We have the the ignition switch replaced, the fuel filter and the fuel pump replaced and it still does it? What could it be, we are running out of money and ideas. Please help.