I have and 03 3.0 and i get a knocking noise under heavier acceleration at between about 3000 rpm and 4000rpm. just did seafoam and oil change with no luck. any ideas of what it could be??? really could use some help because i dont want to drive it like this, so 'm stuck driving my 1983 caprice classic (with no shocks and bad breaks). would really like my comfy car back!

 

nobody has any ideas/suggestions?