P0304

Hello, this code indicates a cylinder number four misfire. This does not indicate that a spark plug or a coil has failed, but merely that for cylinder number four, there is a measured misfire that is happening consistently enough to set a trouble code. Hands on testing is needed to find out what is happening. As you have replaced a plug and coil on the affected cylinder (make sure you have treated all cylinders, or at least the correct one!), I would next move to perform a compression test on the engine and see if cylinder 4 is low or leaks down. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops