P0304 4th Cylinder misfire on 2002 Mitsubishi Diamante

I was driving one day recently, stopped for the lights(car is idling) I heard a continuos popping sound and the service engine soon light came on, I drove with it for 5 miles it stayed on . The next day took it to Autozone to read the code and it turned out to be P0304, misfire in the 4th Cylinder. After that I drove to my gym with the Service Engine soon light on and went to my gym for an hour or so, came back started my car the Service Engine soon light is off now. I checked for heartier core even though my car has been rectified by the dealer from whom I bought as its a 2-year certified warranty car.I checked the passenger side carpet, it dry and also the right side of the gas pedal everything is dry, my AC runs good no antifreeze smell, i checked the fluids my self (coolant, Engine oil, Transmission oil) everything is normal. The car starts fine, and runs smooth don't have rough start or idling or during acceleration. Sometimes a slight burning smell comes and it was there previously itself as I have slight oil leak. Do I have to worry about this or I need to take it to a mechanic for further diagnostics?

Model: Diamante
Engine : V6
Transmission: Auto

Asked by for the 2002 Mitsubishi Diamante
How many miles on it? what maint. have you done ? what kind of parts ?--cheap aftermarket , premium aftermarket, or OEM mitsubishi (preffered)?.. Do you do any of yor own maint.?