Hello everyone I was wondering if I could have a helping hand so here is the story I was driving my Sti was waiting at a red light when the light turned green I accelerated once I reached about 20 mph the car seemed like it wasn’t giving me power and seemed like it was bogging and when trying to accelerate or go past around 20 mph it shut off completely I pulled over and my check engine came on I read it with a scanner and it said p0304 which is a misfire in cylinder 4 so would it be best to change the spark plugs first? 

That was the only code?

how old are the plugs?

what year vehicle? how many miles? have you owned it for a while or s it new to you?