I have replaced every ignition coil and spark plug costing me about 280 dollars and still have problems with my cylinder 1 I checked to make sure all parts are working. I suspect it's the wire that you plug into the ignition coil as it doesn't affect the car if plugged or not but the other 3 do.
My car has 32000 miles.
My car has an automatic transmission.
Diagnostic Trouble Code P0301 means that Cylinder No. 1 is misfiring but the causes of that can be very varied. The fuel injector could simply be dead or there is little cylinder compression due to a burned valve or leaky head gasket. Test for power TO the coil as if there is no power to the coil the supply circuit (including the PCM) has to be diagnosed to find the fault. If there is power to the coil, I would check to see if the fuel injector is functioning and check compression. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a misfiring diagnostic and the responding certified mechanic will get this diagnosed and resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.