My check engine light came on a month ago on my 01 GT so i plugged in my Diablo tuner to pull the code and it said cylinder 3 & 4 misfire and exhaust bank 1 lean. Which I'm assuming is because cylinder 3 & 4 is not firing. So i replaced my spark plugs because it was getting to be that time and 3 of my 8 plugs had excessively wear in one way or another. So they are now brand new. Resets the codes, drove the mustang for a bit and then the check engine light came back on. Now it's just cylinder 3 misfire and exhaust bank 1 lean. cylinder 4 is now fine. My timing gun confirms that the harness for #3 is not firing so i swapped the COP(Coil over Plug) and spark plug with a cylinder i know works and still cylinder 3 does not fire. I could tell the spark plug had no signs of combustion but definitely fuel was present in the combustion camber. Also in my Haynes manual it said to check for 12V coming out of the harness for that cylinder with the ignition on but not starting the engine and wont you know there is voltage but it wont fire the coil when the engines running. What is the fix?