A good chance all your problems will be from the multitap to the house. Many systems redo the entire drop with good RG-6 and redo all the connector. As mentioned “jdahl1979” check at the node and make sure the part of the FM band is free of interference and if it not, there is a good chance that the problem come from the head end. Make sure all your head end connection are tight and with good RF connectors.
Good luck.
