Hi all. I have read multiple threads on this leaking plenum business, and I think I may have this problem.
When in neutral, holding at a steady rpm, (3000) I get a knocking noise.
I popped the hood to investigate closer, and when I raise the rpm slightly its okay, but under hard acceleration (neutral or while driving) I get a horrid knocking that comes directly from the intake.

There also appears to be some oil leaking from the valve cover gaskets, but I'm not totally sure.

Anybody else have these symptoms? Let me know, thanks!

 

take off the air cleaner and look down into the intake manifold. If you see oil pooling on the pan you have a leak. The oil leak for the plenum is an internal one so you woudlnt see it out side the engine. Knocking is usually a symptom of a plenum leak after its goten realy bad. Has the engine pinged before?

 

I don't know... I bought the truck like this, knowing it needed some kind of repair. Is it worthwhile to remove and replace valve cover gaskets while repairing the plenum?

 

If there leaking id say so. You dont have to remove the valve covers to remove the intake manifold but your going to have the engine riped apart anyways. You could also opt to get thoes sweet mopar proformance valve covers while your at it