engine knocking. "cold" start.

My engine seems to be knocking this last couple of mornings. Temps are around 45 at night. Not that cold. The knock is there until warm, sounds deep. Not the normal tick. Oil level is good and was changed 2k miles ago. Only 17k miles on it.

Thoughts?

 

Try a tank of 91 octane and see what happens?

 

Piston slap, worse on cold mornings.

My '03 Tundra sounded like a Powerstroke.

 

Is that anything to worry about?

 

Does your engine sound like this?

http://www.youtube.com/watch?v=sK8Rdr69UyA

 

Put 125k on it before I (stupidly) traded it for a Duramax.
Never burned a drop of oil, used oil analysis was clean.

 

Hard to say. Kinda at the beginning of the video.

Hmm well thats good. Maybe ill just take it in and have them keep it over night so they can hear it in the morning. Oil pump maybe?