weird exhaust noise

[strobed04runner]

hey guys. i have an 04 4.0. i had an exhaust put on last year by midas. new pipe bent all the way back with a cherry bomb straight through muffler. recently my truck has been making a weird almost weedwhacker noise from the exhaust. no leaks anywhere. any ideas . my check engine light also came on not too long ago for lower bank 2 cat below threshhold. could this noise possibly be a bad cat? was gonna change the sensors first. thanks for any input

 

[Stuck CAPS]

The cat is the most likely the problem.. with the check engine for the cat should have been a sign to replace or at least look at it (or get it looked at).

 

[strobed04runner]

Ok thanks man. Well the noise has been goin on for the last month. Didn't think anything of it at first. The noise has been progressively getting louder though. Check engine light only came on last week.