08 5.4 Knocking on start

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Sep 3, 2013 | 02:37 PM

2track

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Cross-Country

Joined: Nov 2003

Posts: 74

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From: Michigan

08 5.4 Knocking on start

sounds like a rod knock on startup but quiets after idle down. what gives and can this be a big problem? 75000 mi.

Sep 4, 2013 | 10:57 PM

Bwulf259

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Joined: Sep 2013

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There is a rubber hose that is plugged into the passenger side valve cover it runs behind the Intake manifold and plugs into a vacuum line on the drivers side this thing gets hot and dry rots it causes a minor vacuum leak I replaced mine with some hose from napa for around $3 it should fix your issue

Sep 23, 2013 | 08:48 PM

mickey F-150

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Joined: Sep 2013

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Its a lifter. When u leave it sit for a bit it looses pressure so when u start it its tapping till the oil pressure gets built back up. It prob only taps for a few seconds. But a bad lifter can lead to other problems so its best to replace it as soon as you can