There's a rumble noise coming from the engine at about 2K rpm and higher. It started after I installed the 3'' downpipe. I'm not sure if the downpipe is vibrating on something. The downpipe did clear the ACD. If it was vibrating something down there that I'm not aware of, will it hurt the engine or downpipe in any way? And is there anything I could do to move the downpipe? Thanks, any help will be useful.