Prius 3 knock and miss fixed!

After running fine for 5000 miles, my Prius suddenly got the dreaded Death Rattle while idling at a store. I did a bit of research, followed some good suggestions from here. But for mine, it was NOT the injectors nor the fuel pressure regulator. I changed all them, same problem: knocking, clattering, sounds like a bad piston...
Then there was a video on youtube about the coil packs going bad. Bingo! same sound. I purchased one from Advanced Auto, installed it and viola!!! running smooth as silk...
While more pricey, the coil pack was returnable and available today, and fixed my problem. Good luck. Dragon