96 running really ruff! please help!
 

I have a 96 miata and was driving to work and the check engine light came on and started flashing. The car started running really bad! It was shaking like a Harley V Twin. I took it and had the codes read the number 2 cylinder was miss firing and there was a code something about the crank shaft position something something. I took the number two plug out and it was fouled pretty bad so i replaced it and the rest of the plugs which didnt look very good. Still runs really bad! What is the crank shaft postion and could it be the reason it runs like poop?