Fluttering noise when accelerating

[GabeS14]

I just noticed a weird fluttery noise when i accelerate...usually in 2-3 gear or 3-4th....sounds like a sort of tapping or flapping but not nocking... ..
any one have any ideas what this might be?
seams to come from the drivers side...i can hear it from my window...

[MELLO*SOS]

Didn't give much info to go off of. What motor do you have? Can you put a video of the noise...

I guess exhaust leak due to a snapped stud or blown out exhaust gasket.