bumping noise under car on a 2011
have a bumping noise under car that has been there for over a year an just keeps getting louder, it will do it when driving an sounds like a exhaust pipe moving. I have checked everything an cannot seems to pinpoint it and it does not do it all the time. Talked to the ford dealer an they said they will just have to start trying things because they have not run into this before. Any help out there?