Quote Originally Posted by 2003GrandPrixSE View Post
Ever since I put those red inserts from ZZ Performance in the upper mounts, engine movement has calmed down quite a bit plus lower mount is solid now not hydraulic. Thanks for info on rotors, I couldn't figure that being a problem considering AC Delco parts. I'll check sub-frame and other parts Quicksilver mentioned. Gonna check torque on lug nuts too. Thanks for input guys.
I had a similiar noise, the metal brace that is above the air box in the engine compartment was loose. the noise was a random creaking noise. good luck