I have a 2006 mustang gt with 125k miles on it. In Jan it threw a random misfire code P0300, so I changed out all 8 of the spark plugs. I thought it was bout time. About a month ago I threw a P0301 so I replaced the coil pack, which appeared burnt on the coil end, on cylinder 1. Seemed to fix that issue but a week later I threw P0303. I tried a new coil pack, which also appeared burnt on the end, but it still says cylinder 3 is misfiring. I also replaced the fuel injector. Every 80 miles or so the check engine light will go on solid, and the scan will come back as P0303. I checked the compression and all cylinders are normal. No intake leaks. There is a slight ticking sound noticeable at idle so I flushed the engine and changed oil to see if it was the lifters or valves sticking...no luck. Still ticking slightly and throwing the P0303 code every 2 days or so. Car runs great, its not an easy misfire to feel but i believe the computer. I just am at a loss and have no idea where to go from here?