It's like clock work if you want to make the noise start, after it starts it won't go away unless you come to a full stop.

It sounds like a scraping or scratching metal on metal noise. But maybe it's a loud air suspension leak?

The 2004 xj8 has new front brakes and I bent the brake dust shields away from the rotors

Any ideas what it could be?

 

Did it do it before you renewed the brakes?

If not, then maybe just maybe something went wrong on the brake parts.
Misassembled caliper to pad springs or wrong pads would be my guess.
Clean and lube the slides?

Easy to check and fix, I think.

Good luck.

 

The noise has been around since I bought the car

 

Could it be a wheel bearing?

 

Your ford engine is pretty bulletproof but the Jockey pulley can fail.

 

The noise is still around, I think I have it narrowed down to the left front. I lifted the back end up and had the wheels spinning at 60 mph with no noise.

I'm not having any other symptoms of a wheel bearing going out but I think I will look in to it.

 

I was finally able to simulate the noise by running the vehicle with the wheels off the ground.

Here is the cause of the noise. It is amazing how loud and deceiving a rattling piece of plastic can be.

 

I love it when a thread comes to conclusion and the final results are posted.
Good honesty.
Glad you found the problem.
Take care.