Originally Posted by BMWOO7

Yes, please do post info on the vehicle for starters.

Also, if it's the exhaust flap in the rear of the muffler, you might be able to just zip tie it open and be done with it.

Allot of folks here do that to gain true dual exhaust out the back and a little sportier sound.

From what has been posted there are no adverse side affects whatsoever to keeping the exhaust valve open all the time, it seems to be like this for noise purposes but actually sounds quite sporty when it's open all the time.

Just for reference, this exhaust flap opens under full throttle or above 3K RPM's which could be why you heard something while getting up to speed.