Last couple of times I've done hard pulls I've thrown the same codes. They are always misfire codes and I always get the rough idle with the SES light right when the codes are thrown. The only performance mod on my car is a jb4 on map 1. Is there any way to tell if this is my spark plugs or my could? I've read about problems with both, but is there a way to tell if it's one or the other?