Hello i hope i can help you with your problem. It sounds like a miss. Have you replaced fuel filters? Check and see if there is an update for your computer at the Ford store.If not its either a fuel pump or a bad injector. I hope this helps.
This does sound like a fuel issue. I would recommend doing a fuel pressure test. Also making sure that there is no restricition in the fuel lines. Also i would do a power balance on the injectors.The dealership might have only did a injector buzz test. Make sure they do it under a load. I hope this helps.