Engine stalls while driving 2003 Expedition

I have a 2003 Expedition and am experiencing the engine stalling while driving. I am then forced to coast to the side of the road and re-start the engine which starts right up. This has been very dangerious for me. I have been in the fast lane of I95 in CT going 70 when it happened. It stalls like this once or twice a week now. I brought it into the Ford dealer and they replaced the fuse box. Any help would be great. Thanks Lou Rawden.