Knock under intake manifold

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Sep 15, 2020 | 05:07 PM

Chiefsdt

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Knock under intake manifold

I have a 01 f150 5.4 Supercrew. I have a knock almost rattle sound that gets worse with higher rpm. It sounds loudest out of the intake. With a scope it is super loud front of intake on passenger side. I had the intake replace a couple years ago and thats when I started hearing it. It got worse about 2 weeks ago. So I replaced the intake again and the knock was almost completely gone. After a day or so the knock came back. Loud as ever! I have read similar stories on here and other sites not one solved answer. Please anyone help me out! I have been tracking this knock for 2 years! Also side note had a remanned engine i stalled a few months before the first intake replacement. Thank you anyone in advance!!

Sep 16, 2020 | 11:59 AM

Lime1GT

Fleet Mechanic

Joined: Jul 2010

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From: Winnipeg

Have you had the valve cover off to check for worn roller rockers?

Sep 16, 2020 | 03:33 PM

Chiefsdt

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Even ran a scope to check pistons and all. It sounds like a ball bouncing in side it.

Sep 16, 2020 | 03:35 PM

Chiefsdt

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The weird part is the knock went away with intake replaced. A day later it came back. I am at a loss.

Sep 17, 2020 | 04:52 AM

96f150

Fleet Mechanic

Joined: Nov 2000

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From: In my House

Almost everyone that has had the knock, has had the Dorman intake. It has something to do with that. I didnt have a knock until i replaced mine almost 4 yrs ago