Rattling when I drive

I am going insane about this rattle from underneath the car somewhere. It only rattles when the car is moving. Rattles harder and faster (and inconsistently) at higher speeds and slow unpredictable rattles when I idle around. The rattling seems to be a little more constant when I am driving at a constant speed on the freeway (around 65mph). It sounds like a spinning noise and it will rattle/spin really fast and then stop and then do it again, but its inconsistent.
I took it to a tranny shop and he said it was the cat so I took it to Midas and they said it was the cat. The next morning I took it to a good mufler shop had the cat and the resonator replaced but the rattleing continues. The mufler guy said he thought it might be in the front suspension, a spindle, brakes, or CV joint but he wasnt sure. I am trying to figure this out so that something worse doesnt happen. I like all four of my wheels spinning ON my car and not flying off at 75mph.
Does anyone have any idea what is going on? Any advice is appreciated. Thanks in Advance.

Scott

[n00b on demand]

heat shields.

[Earthworm]

Normally it's either the heat shields or the resonator that makes noise.

If it's the suspension you should be able to generate a noise by grabbing a front tire and "shaking" it either horizontally (side to side) or vertically (top & bottom). Results would be easier found with the wheel off the ground.

[calisvx]

90% chance heat shields that was killing me too i finally solved it when i found a thread here on heat shileds thanks everyone!

hopefully thats your problem too.