It sounds to me like it may be a heat shield vibrating (similar sound anyway) but I can't find it. Does anyone have a diagram of where the heat shields are on a 2007? I see the one under the van that would be about right under the passenger front seat, that one is not the problem. It sounds more it is coming from inside the engine bay (only I can't tell from where, left or right is impossible to determine by sound).
The noise occurs when the gas pedal is pushed (does not matter how far or how hard) even while parked.
The noise is worse while under load and actually in motion. While in motion the noise happens when the gas pedal is first pushed, then stops. As many time as I was on/off the gas, it was consistent. While doing about 25-30mph, if I SLIGHTLY press the gas pedal down, the rattle was fairly constant (or lasted much longer than any other time).
The only info I got from my wife was that she went down some long gravel road recently (roughly just before the noise) she said she went slow.
The only other thing I could think of was maybe several small rocks where stuck in a heat shield or something, but I could see any or hear any when I banged on the heat shield while parked and I crawled under the van.
Short story, there is a metalic rattle sound every time I hit the gas (happens for a second) at any speed. I hear it while parked and hitting the gas, but the sound is louder under load and in motion.
Wife has put 1000 miles on the van with it making this noise, MPG and everything else seem perfectly fine. No lights on. The sound it just worrying me.