Welcome I'm Chris aka Moose
Below are the Ford diag steps for reception issue if you would like to do or look over them.
Just a heads up, diagnosing and resolving AM issues is hard. Radios are no longer built to work with AM stations in mind since many are being phased out. Often the result is needing a better antenna or a booster. The 2 simple tests are to check the reception without the engine on, to rule out an engine part to blame. Then compare it to another vehicle sitting side by side. If another has better reception then its pretty much a given the vehicle with the worst reception has a weak or poor designed antenna or antenna cable issues.
-----------About me and Just Answer------------
I am in my upper 30's, have a wife and 2 sons. I farm, fish, hunt, build, and coach youth soccer. I work on anything with an engine, been to many schools and classes through my 12 years with the dealership to get trained and certified. I try the best I can to share what I know and or have access to with my customers. Please consider I base my questions and answers to you, solely on the information you give me since I am not there to see, smell, hear, touch, or test. I try my best to be here everyday starting at 3pm central. Rating an answer is required. Please let me know if your not pleased prior to rating or if you cannot rate me so I can try to help a different way. God Bless and have a great day.