alright last night my 1999 Ls Stock was sounding alittle odd. I said hey maybe a heat shield was coming off. well the manifold one is fine, my cat is fine.... as far as I could see. u can't be heard until 3 to 4000 rpm. then 4000 its not there. I really don't think its my bearings at least I hope now. could it be? Its a buzzing sound like a heat shield. car drives fine just that sounds bugs the hell out of me. its around the exhaust and by the block. could anyone help me out or tell me if its the bearings? I over reved when i passed someone the other day

 

If you have the stock exhaust manifold, the welds inside tend to break over time and cause a bad vibration during certain rpms.

If you have the stock cat, the sheild mounted directly to it and insides can rattle.

You can have it put on a lift and have them probe around with thermal gloves as you rev the engine where it vibrates. Good luck, I have a rattle and I hate it, I think it is my cheap header, but could be my shields since I left all of them intact.

 

thanks alot man, yea looks like i have to deal with it for awhile no cash.