Misfiring engine codes P0300, P0305, & P0306
 

After changing the spark plugs, I was informed that I had suspect coil packs on cylinders 5 and 6. (it wasnt the coil packs) I eventually cleaned my throttle body, PCV valve and added a can of Seafoam. After cleaning the PCV valve with carb cleaning spray, I can say it was the PCV valve - approx 1 ounce of carbon buildup came out. The cleaning of the throttle body, new plugs and seafoam didnt hurt either.