I was having a bad misfire and I checked and replaced all the cheap stuff first....wires, plugs, etc. Well I then replaced the Opti, waterpump, ICM, and fuel filter. Nothing worked my car was still misfiriing. So I pulled the valve covers and the intake rocker arm stud on the the #3 cylinder was broken right in half. That was a good $500 lesson

Anyone ever broken a rocker arm stud?

 

Stock stud? Stock rocker?

 

Stock stud...aftermarket 1.6 roller rocker...LT4 valve springs.

 

Yes had the same problem. Buy some good ARP/CRANE studs you should be fine. Take a look at the pushrod and rocker for damage. Make sure no metal hiding in there.