Id be interested in how he tested. My 13 has almost 125k miles and Ive had one misfire from a coil pack failure and one due to a partially plugged injector. All injector tests came back good but replacing it fixed the issue. Is it a P0300 or 301,302,303,304? At least gives you a spot to focus. Also, check your hoses on the intake- unmetered air getting into the inlet can cause a miss. Theres the obvious hoses on the top and a tough to get to one behind the dynamic chamber.