I am having an issue where in 2nd and up (1st goes by to fast to hear it)about 5000 rpm there is a loud flapping/rattling noise from in front of the driver. From what I can tell there is not much power loss if any at all. I have a 6 speed sport with 50,000.
Could this be a sign of coil and plug failure? I have noticed that my cat glows a dark orange at night after a decent drive.
I am unsure if they had been changed by the previous owner.

It does not sound like MIAC.

The problem is intermittent. I cleaned the ESS and reset the NVRAM, and the problem seemed to disappear.

Thank you,
Any help will be appreciated.

 

Could be an intake valve problem.

However, if your cat is glowing, it's either dead or on death's door, and it will get dangerous to parts and to your car (catching fire) the more it is driven. Federal cat warranty up to 80,000.

And cat failures are usually caused by coil, plug, and/or wire failure.