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The coil is the most common thing to cause a engine misfire so you could start by swapping coil with another cylinder to see if misfire follows if so, replace the coil. If not you will need to use a spark tester to see if coil produces good spark. If it doesn't then you will need to test wiring between coil and pcm to see if problem is wiring or PCM. If good then use a led test light to check for injector pulse, if no pulse then check wiring between pcm. It would be more likely a coil issues because injectors would usually set a different code. Then last stem would be trying a cylinder leak down test to see if that could determine anything before pulling head but either way head would need to be pulled if it gets good spark and injector pulse. Let me know if you have more questions, thanks.
If compression is too low for fuel to combust then the fuel would go right into the oil without igniting so the spark plug would not look any different. All of the things you mentioned would cause low compression so fuel can't ignite. At this point I'd do a cylinder leak down test which should tell you where compression is being lost. If you verified its getting good spark and fuel spray then mechanical is only possible problem left. Let me know how it goes or if you run into more questions, thanks.
Some engines work differently, rule of thumb is 100 psi should give you some type of combustion but I've seen it go much higher and not. Let me know how it goes, thanks.
Good to hear, I'm surprised only 1 cylinder was effected. Thanks for update and have a great night!
Nice find. Thanks again.