2016 Ford Expedition Limited does not start at least once a week. Dealer cannot find the problem. Help:
How about some more information . Such as - what does it do , just have the starter turn the engine and it does not begin to run on its own , nothing happens when to try to start it , what does the dealer do to get it start or do they not have a problem .
With no real description of your problem or what was done to identify it… there is little chance folks on the internet can diagnose your problem when mechanics with their eyes, ears and hands on the car can’t.
Find a better mechanic. Maybe a better Ford dealer but that isn’t necessary. A good independent will do.