Hey there...been awhile, been too busy with my other mode of transportation (gs500), but recently my 2001 (75+K) has had significant loss of power. (going uphill biggest difference) I do the usual oil change, fuel filter, engine flush (dealer $$$$$) . Saw a slight improvement, and now i hear a rattling at low rpms. Asked the dealer bout it and he said just heat shield?? ehhh help. THanks in advance.