Rick's 06

With the rattle on cold start ups and when you're letting off the gas points to chain rattle to me. Under constant load your chain should be tight, but when you let off the gas the slack side will slap around if the tensioner isn't doing it's job. If it's been doing it a while, I'll bet part of your guide has already broken off and sitting in the oil pan. You could pull your pan and see. Finding that would definitely give you your answer.