2001 nissan xterra with the 3.3 wouldnt start so i pulled the codes and found it could be the distributor, i found the crank was turning the cams and found the timing belt was stripped so i replaced it and reset the timing now the car wants to start but acts as if its misfiring really badly and its pulling a p0300 code which from what i found is multi cyclinder misfire. what would cause this?