Tune Help
 

Hi i have a full bolts on already and im getting a error code p0300 multiple random misfire they told me to get this fix i have to get my car tuned. I already reset it multiple times but it keeps on coming back, changed all the plugs to new spark plugs and inspected all the coils and everything looks ok. i want to get my car tuned but i dont know what to do first. Should i just go to the tuner or do i have to buy something first?