I can't tell if I have an exhaust leak from my donut gasket or it is something vibrating but it sounds like a low pitch rattle. Has anyone ever had a leak from their donut gasket after putting an exhaust on. BTW the sound is not always there and it was not there when I first put it on...

 

An exhaust leak will sound like a flutter. Maybe your exhaust is rubbing somewhere under the car. Possibly your rear O2 sensor hitting the body?

 

just check underneath make sure nothing is rubbing against the underside. Look at all the connections and see if any of them are loose.

 

Are you getting headaches and just feeling tired? If you are it good be an exhaust leak. Just jack the car up and feel around the flanges and you may find your culprit.

 

haha x2