What would cause my Toyota sienna engine to cut off while driving down the road and not start back up?

May be fuel related,fuel pump,or may even be a timming issue,such as timming belt breaking.

could it be fuel pump,or may even be a timing issue,such as timing belt breaking?

In my case it was alternator, it was got stuck and not spinning at all. When I tried start it makes sound like engine hard turning and dead (first I thought starter or timing belt but it was alternator stuck like frozen . Glad some guy had jumper cable and more power makes starter run broke belt on alternator and I drove home only on battery couple miles

Same here, 2004 Sienna. Just won’t turn over... 1/2 tank of gas and a jump didn’t work :/