The engine on our Ford Expedition (2003) has started quitting for no reason. The engine light does not come on. We might be driving and it just stops or stopped at a light or turning into the driveway and it just turns off. Often it we simply turn it back on and it is fine but occasionally it is difficult to restart. Any ideas on what this might be?
So it dies with all lights off, just like you turned the key to off? Or do the lights (alternator, etc) come on and you have to restart it? Does it readily restart?
Could be the ignition switch or main relay, which I suspect that truck has.
Edit: it does not appear to have a main relay.
My neighbors 2003 did this last week. It was an intermittent run issue that turned into a tow truck ride home all in the same day. no check engine light either.
He and I followed this link and found the main Fuel Pump Relay was failing. Unfortunately you have to replace the entire power distribution box if you do not have access to the relay and a soldering iron because this one is soldered into the distribution box.
There’s not enough info known to make much of a guess but you should have the truck scanned for codes as a start. Many chain type auto parts stores will do this for you free.
If one assumes no codes are present a wild guess might be an intermittent fuel pump or fuel pressure sensor although there are other things that can cause a problem like this without setting a code.
Inspecting and cleaning the battery cable ends and posts might not be a bad idea either. Several of my Fords have gotten a little oddball stupid at times over something that is apparently trivial on the surface.