I have a 92 3.1 with 215K on it. Only when the car is warm and I stop at a light the idle gets rough, starts to surge and then dies. This does not happen when I have the A/C running though. OBD code says the EGR valve is bad, but it was bad before this started happening. I thought a bad EGR valve would just reduce gas mileage and make for poor emissions. Any ideas?