Why is car shutting off while running? on 2004 Ford Expedition

180K Car randomly shuts off while running. Even at 60 MPH!
5 X per month for last few months. Check engine and Battery lights goes on. I slow to 30 MPH and put in neutral and it starts right up. Otherwise runs fine. Have previously changed ignition coils. Mechanic has had car and finds nothing.
Computer check shows nothing wrong. Help/suggestions.

Asked by for the 2004 Ford Expedition
scan for codes and post so we can adv
Mechanic is stumped.
I have the car back and still experiencing problem.
I am the driver. Sorry, don't know any codes.
1 more answer
same problem with my 04 expedition, after many trips to shops with no answers bought hand held scanner and kept it connected till I got a code out of computer PO231 "secondary fuel pump circuit low voltage" This code always cleared when car restarted is why shops could not find it. Bad fuel pump relay that is not serviceable & need to change out fuse panel.