Yes you can have a problem with a fuel injector that is either dirty or leaking. But in my opinion it's just not as common as finding a malfunction in the ignition system.
Malfunctions such as a bad spark plug wire or even worn or fowled spark plugs seem to be a more common cause of a cylinder that is not firing correctly.
Checking ignition related misfires
In some cases if you have an ignition engine misfire a trouble code will be stored in the vehicle's computer. In most cases this would also turn on the check engine light. In rare instances the code could be set as a pending code and you would need a scan tool to read and diagnose it.
Often a set diagnostic trouble code can lead you to the cause of the cars problem. In other cases further diagnosis by an experienced automotive technician may be required. If you have an ignition engine misfire in combination with the check engine light the code should be diagnosed and repaired before you move on to further diagnosing ignition system.
Checking electrical connections
Both the power and ground side of the circuit where they originate can be susceptible to corrosion and poor connections. When it comes to testing for individual spark to a cylinder I use a ignition spark tester. This is a very effective way to verify that the proper current is being sent to each spark plug. When in doubt a quality auto service manual will provide diagnostic tree charts for the symptoms that you're having. For more information about this website and additional posts you can visit the online auto repair home page.