Hard to explain but as you traveling down the road and start to accelerate you hear a noise almost feel vibartion, reminds me of a loose exhaust shield. It has been to dealers twice and two local shops. No one can figure out where its coming from. I had orginally replaced top and bottom motor mount, check all exhaust shields, checked that manifold brackets and bolts tights. Noise does not appear under heavy acceleration. Maybe someone else could of had simlar problem. thanks for any help.

 

are you running your AC when this happens, or does it happen all the time?

 

If you can try to strap the exhaust hanger tight where it attaches to the front cross member and see if it goes away.