Well, I got the mustang out today and noticed it seem to be running like ****. The check engine light came on right before we got home. I pulled the codes
PO316 misfire before first 1000 revs
PO308 #8 misfire
I want to think it's a fouled plug with that combo, but it couldn't be more than the cop or injector could it?

 

I'd try those first.

The Cobra actually was misfiring due to the COPs being cracked and arcing across.

So try plugs and cops first, then go from there.