I think my next course of action is to replace the timing belt as I suspect it may be the culprit. Even if it's not, this timing belt is way overdue for a replacement. My thoughts currently are that the belt skipped some teeth. While I wait for the parts (and tools) to arrive, I decided to send an endoscope down each of the cylinders.

Cylinder 1
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Cylinder 2
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Cylinder 3
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Cylinder 4
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Immediately I noticed that the first cylinder was very sooty, and that each cylinder also had notches on them that were indicitave of valve interference. However, since all of the valve notches seem to be the same on all pistons, and the fact that I found an aftermarket replacement pison with the same markings leads me to believe that these marks came from the factory and are not there because the valves are hitting the pistons.

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