1995 Pontiac Bonneville Dies while driving

My car will die while driving at 55mph. Sometimes it will start back up and other times, will not fire again. I had a friend at work read the codes and they were...
P0325 Knock sensor
P1670 QDM 4 Failure
and
P1406 EGR Pintle Position

I can't find online what the QDM 4 is.

Also, when the car is running, the exhaust stinks, almost like eggs. Should I look into a new cat. converter also?

Thanks guys!

Brian