P0305 code

That is correct, could be the ignition coil, spark plug, fuel injector ect.... Try swapping the ignition coil to another cylinder and see if the misfire changes to the cylinder you have moved the coil to.

It can also be as simple as a spark plug. If you are failing your smog check, you may be elgible for repair assisstance in the amount of $500.00 Call us and we will walk you through the program. 947-2555