It is not my CompG in question, rather someone I work with. He had purchased a used 03 GP GTP from an elderly couple. This last week his wife had drivin it and said it was knocking rapidly and when she pulled up to a stop light the car had stalled and died. It had started back up and she drove it to the nearest parking lot and left it afraid to drive it further from home.

They had it towed to a shop and the mechanic said the engine was blown. But it started back up after that. Oil was clean and fresh. No aftermarket mods on the car. They dont beat on it. So i was stumped as to what the problem was. I was leaning towards the timing being bad or the balance was off.

What are your thoughts?

First thing check the supercharger for endplay in the pulley.

The other thing could be the oil pump is starting to go and was temporarily starved for oil.

sounds like a spun bearing, the supercharger coupler wont cause it to stall and it sounds like a bunch of rocks in the supercharger

Both theories that killer and notallthere are very feasible. Has the knock come back, perhaps muted, at say between 2000-3500 rpm and then goes away again?

I am fairly confident that the balance shaft is not the cause. The balance shaft would cause the motor to shake but not cause any knock if it were not properly timed.

Ok I will let him know. Haven't seen him but will give him the info thanks!