Okay. I agree. If this were spark knock more than likely it would have changed. In my opinion, that leaves one thing based on what you are describing and that is a valve train issue related to oil pressure like a lash adjuster or lifter. Basically, at higher RPM the lifter just doesn't stay pumped up and it starts clicking. Then when the RPM comes down it is able to pump back up and the noise goes away.
Unfortunately, there is no way to test them in vehicle. Basically, if they are noisy they need to be removed and cleaned or replaced.
Last thing I can suggest is if the noise is loud enough to get on a video, take a recording and post it to the site and I can help identify if this is a lifter/lash adjuster noise.
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Thursday, May 16th, 2019 AT 11:51 AM