Signs of a bad EGR valve

Hello I have a problem we own a 97 lhs chrysler. When my husband drives the car and stops at a light the car will shut off on him. He can start it right back up. Just interested if anyone knows what the problem could be. Let me tell you what we have done to the lhs so far we had replaced all the fuel injectors, the fuel pump, spark plugs. Now it is at the chrysler dealership they told us it was the o2 sensors so replaced the left and right one. The problem is not fixed. Now they are trying to tell me the egr valve is bad can that cause the car to shut off. Some one please help we are putting so much money into the car and the problem is still not fixed. ?