Engine bay rattle

[thebrakeman]

When driving, I'm getting a rattle at around 3500-4000 rpm.
It's most notable in the lower gears, but I'm assuming it's there at higher speeds, too.
It sounds exhaust-related, either a heat-shield, exhaust manifold, etc, but I can't isolate it, since I can't get the noise when parked. Putting in gear and holding the brake does not get the noise either (nor do I like getting it up to 4000 rpm in drive while holding the brakes!).

Anyone ever get this? Pointers on where to look, where to poke?

 

[Bill MacLeod]

To find a broken heat shield weld, I've used a large screwdriver handle to tap on the exhaust.

Recently heard that the 4th gen V-8 have a problem with right side maniflod cracks? Hope this doesn't apply to you. (or me)

 

[waskly]

probably needs a muffler or cat. something broke apart.