PO104 is generic, -never heard of that one coming up on a Ford, but it's -
Mass/Volume Air Flow Circuit~Intermittent
Sounds like the MAF sensor to me and yes , you'll have all kinds of starting/shifting and drivability issues if that's happening.
A 401? . If that's the case, punch PO401 into the search bar on this site for a wealth of information, pictures, diagrams,video and instruction.
Next step is to replace your problem = Maf Sensor