My 2011 f150 have a noise below the engine where it connects the catalytic converter i

Is the check engine light on? Are you having problems accelerating? It sounds like the insides of the cat maybe breaking apart. If that’s where the noise is. Overtime this will plug the exhaust and make it hard for the engine to breathe This will be noticeable as you will not be able to go very fast and Exceller rating will be very limited