O.K., well all those comment make me feel a little better. It reminds me of a diesel as well. Just did 3rd oil change since I got it. Using Rotella 15-40, a bottle of Lucas,and a Purolator filter. Thought the Lucas would've quieted it down some,but no.Next oil change I will try the marvel mystery oil. Has new injectors(Ford 4 hole), and fuel pump (Bosch). Thank you all for the replies.