engine died - would not start

First of all, you have to be careful about the code you say you have. What type of tool did you use to retrieve this code? I say be careful because you have listed here that your code P300 (which most likely you meant to say P0300), is multiple misfires detected. On GM vehicles a P0300 simply means that a misfire was detected, not necessarily on multiple cylinders. It would be best to narrow down exactly which cylinders where misfiring and go from there. Any coolant and / or oil leaks coming from intake manifold area, near the front and back sections (closest to the serpentine belt and the transmission ends)?