The pcv valve buzzes loudly on my 5.4 engine and if I go at highway speeds for a while when I stop the engine stumbles a bit. It seems like there is too much vacuum. If I pinch the hose going from the valve to the manifold the buzzing stops. Any help would be appreciated.

 

Hi pbjames1 and welcome to FTE

Have you tried replacing the PCV valve? I cant think of anything else that would cause it.

 

That should fix it.

Best thing is a new PVC Valve only cost a couple of bucks!!

If only all the parts were that cheap.

Good luck

 

That would be nice eh?

 

Yes I replaced the valve. It doesn't help.

 

I believe that this has something to do with excessive crankcase pressure. My old 77 did that due to the blowby in the crankcase. This may not be the correct answer in your case though.

 

PCV valves are plastic housings with carefully machined steel poppets inside. There is a very specific flow vs. vacuum requirement. If you have buzzing, your steel poppet is bouncing back and forth between the seats. I think you may have a PCV hose crack which is not permitting enough vacuum to reach the poppet. It raises a bit, then falls, then raises, then falls.

 

Hi, did the problem ever get fixed?
i have the same prob with my 97 5.4