I have a miss on Cyl 4. I am getting Spark. I am having trouble removing the spark plug. But I checked spark at the wire boot. Prior to this there was an electrical issue which blew two fuse causing windows to not work. I replaced fuses. Plugs were replaced at 90K and it has 151K on it now. Could it be the injector or injection module? Also, there was some oil in Cyl 4 plug hole which I was able to clean out with a screw driver and piece of rag. The spark plug is really stuck and I am afraid to break it. Unfortunately cyl 4 is in the back on passenger side.
It could be the injector, but I would look at the spark plug first.
Make sure you're removing it with the engine stone cold. Spray some penetrating lube on it, and let it soak in. As long as your socket is seated properly on the plug, you don't really need to worry about breaking it, and you can use a good amount of force. There's a chance it was cross-threaded, so be ready for that situation.
There's more misfire info in the FAQ topic.
