I fired up my 1973 C20 454 today, (only drive it like once a week) and it was making a weird chattering sound from under the hood. Of course I pop the hood to investigate and after about 10 minutes of searching for the noise I found it, it was the PCV valve chattering and kinda vibrating! I looked inside it and the little plug thingy that's supposed to move was moving violently! The PCV valve is only about 2 months old so what could be causing the darn thing to do what it's doing? Oh and there was a slight bit of oil residue around the PCV grommet in the valve cover, never seen that there before.
