Pontiac Repair: Car advice, buick regal, vover

Question
I am currently working on a 1998 Buick Regal 3800 type 2.  It has a VERY loud knocking noise coming from the top of the engine.  It sounds like it is coming from the rear head.  It starts, but has little power, and misses.  Any ideas?  Thanks for your help.

Patrick

Answer
Hi Patrick:

First though is a broken valve spring more than likely a intake valve. take off the valve vover and take a look at them. hopefully it just broke off 2 or 2 winds of the spring and the valve is still being held up into the head. If it broke in the middle chnaces are the valve is hanging down enough that the piston is hitting the valve which is not a good thing! good luck :}