You could try to swap an injector with another cylinder to see if misfire moves, if so replace injector. You can also do a compression test to verify compression in that cylinder in not low, if so you have internal engine problem. It is common for the exhaust valve in this vehicle to stick causing this code, you could try to run some top engine cleaner through engine to try and remove any carbon buildup and add valve lubrication additive. If none of these things work you will need to bring vehicle in to have valves looked at. Let me know if there is anything else I can do to help. Thanks.
P0302 Cylinder Number 2 Misfire Detected