Since I picked it up new in 04,it sometimes,not always, has a two second rap/knock when it starts.As soon as oil pressure hits it,it's quiet.Runs fine after that.It has not become worse in the last eleven years/73k miles.
Has anyone else experienced this sort of noise? I've thought that it could be rod related,but could it be something in one of the heads? Lifter? Thanks.

 

Sounds like the hydraulic lifters. Theyre more than likely leaking down between run times.

 

lash adjusters for sure, after i started running full synthetic, mine stopped making that noise

 

I poured a shot glass full of Lucas oil treatment in mine and haven't heard another peep out of it.