Hi, I am John Mc, a Ford dealer tech. I hope I can help you quickly and accurately. One moment while I work on your problem.
If your gas cap light is still coming on after replacing the cap chances are you have an issue with one of your evap (gas vapor) hoses on your tank has come loose. You will have to follow all the lines off of the fuel tank to find which one is loose. If none are loose it is possible you have a vapor management valve that is not opening or you have a small hole rubbed in one of the hoses. If that is the case you will need to take it to a shop that has a smoke machine leak detector. This machine fills up the fuel tank with smoke then they can search all the lines and see where the smoke is coming out. Once they find it they can repair it. This can get pretty complex trying to find the problem so if you don't see something obvious I wouldn't go too far trying to figure it out yourself.
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