Pitter Patter Sound--Manifold --96 XLT-HELP

[96 Explorer XLT]

I started to hear this pitter patter sound-almost like a knocking of an engine. Looking in the engine, to the left, the manifold has this screw cap (best way I can describe it) on it. Its about 2x the size of a standard soda plastic cap. And this "screw cap" is leaking air from the top, from what I can tell, which appears to making this pitter padder, knocking sound.

What is that cap and its purpose on the manifold? Looks like a simple part to take on and off.

Have a 96 XLT 5.0

 

[Turdle]

I started to hear this pitter patter sound-almost like a knocking of an engine. Looking in the engine, to the left, the manifold has this screw cap (best way I can describe it) on it. Its about 2x the size of a standard soda plastic cap. And this "screw cap" is leaking air from the top, from what I can tell, which appears to making this pitter padder, knocking sound.

What is that cap and its purpose on the manifold? Looks like a simple part to take on and off.

Have a 96 XLT 5.0

Could you take a picture-and put it on a hosting site like

www.photobucket.com

then put up a link here--

 

[96 Explorer XLT]

I think it may be a check value on the passengers side manifold??? Its righ on top of the manifold. It doesnt appear to be a big thing to replace. I take a snap shot.

The ERG Tube actually fell off a few months ago (very strange for that to happen) and thought it was coming out again but thats on the drivers side.

My power steering pump is going so Im having it replaced Friday and this just surfaced today.

 

[96 Explorer XLT]

Im about 100% sure its the ERG tube. Same systems as last time, identical results and sound. I believe the ERG tube is completely gone again.