Found it.

[Asnes]

I was going bonkers but not enough to deal with the issue until today….

There has been a metal on metal rattle / vibration since almost new but only at around 2,000 rpm and only under certain engine load conditions like accelerating in 8th gear on the highway…. Car has a little over 17,000 miles these past 1.5 years.

The rattle would intermittently go away, get louder, change frequency…. It would sound sometimes like a loose nut, but a nut that was slightly oversized for the bolt threads it was on, and would rattle / vibrate…

I tore things down today… I believe I have located the issue!

Going back out to drive and test

Video:

View: https://youtube.com/shorts/ooJ1d3DdmY4?si=cBYdvyJ4rn1Bje6J

 

[dreamalaska]

Wow, congrats on finding it! You should change the title to “It wasn’t a brain tumor and I wasn’t just hearing things!”

There’s a recent YouTube video of someone finding a factory workers lost wallet in their vehicle years later.

 

[Jeremy996]

Back in the day, the Leyland workers used to put things into box sections or door voids just for laughs. It was not unknown for a worker's packed lunch to be 'disappeared' in this manner by his colleagues.

 

[CountyV8]

My friend Mike found a BL donkey jacket under the spare wheel for his new Austin Alegro,

 

[Clark Kent]

I was going bonkers but not enough to deal with the issue until today….

There has been a metal on metal rattle / vibration since almost new but only at around 2,000 rpm and only under certain engine load conditions like accelerating in 8th gear on the highway…. Car has a little over 17,000 miles these past 1.5 years.

The rattle would intermittently go away, get louder, change frequency…. It would sound sometimes like a loose nut, but a nut that was slightly oversized for the bolt threads it was on, and would rattle / vibrate…

I tore things down today… I believe I have located the issue!

Going back out to drive and test

Video:

View: https://youtube.com/shorts/ooJ1d3DdmY4?si=cBYdvyJ4rn1Bje6J

If that's the fix I'd glue it back in place as a good luck token.