Ebc

03 f150 5.4L
Rattling noise coming from intake manifold and valve cover passenger side. Only slight noise at idle sounding more like a worn idler pulley bearing. Rattling only happens at about 2000 rpm. No codes and runs strong. Replaced timing chain kit and noise is same.

10thGenScab

Take off the belt and run it. Does the noise go away?

Ebc

I did run it with belt removed and noise is still there.

white89gt

Maybe your PCV valve?

Ebc

I removed and plugged pcv from valve cover to see if any changes in the rattle sound with engine rpm at about 2000 with no difference in sound.

Canuck1414

What did it turn out to be?

white89gt

I highly doubt you'll get a response. This was nearly 3 years ago, and all 3 of his posts were in this thread.

Canuck1414

Then it goes no where and I’d still be in the same spot as if I didnt ask

white89gt

Okey dokey.

Ebc

Howdy fellas, I was told one of the vacuum lines had a leak. I was helping a friend out and a tech found the leak via smoke machine. Not sure which specific line it was. Hope this helps.