I spent months trying to track down a bad ticking. I pulled the valve covers and didn't find anything. I next installed headers and solved all but one noise. I finally swapped the valve coming out of the top of the exhaust manifold. I shook the new one and it was quiet and the old one made noise. Now it is so quiet i can't believe it. I used a stethoscope to pinpoint the noise. I never found a post about this so if it help others that would make it worth all the trouble.

 

so you pulled your heads and replaced the valve? Im confused

 

i think he is talking about something to do with the egr system...

 

Coming out of the top of the exhaust manifold is a pipe running to a black piece that contains a valve so air can only go one way i believe. I put a supercharger on so i rerouted the hose but i think it goes to the air pump or something like it. Its obivious if you look under your hood on either side of the engine by the valve covers coming from your exhaust.

 

he replaced a AIR check valve