my 2000 se has a severe exhaust leak but i am unable to locate it....the air seems to be escaping from where the 2nd pipe back, on the drivers side is mounted the the manifold....i assumed it was the mainfold gasket but replacing it has made no difference...it sounds like a loud sputtering sound, and she is running rough at idle with reduced power if you try to drive in in the driveway...................suggestions?