This reminds me of my old room mate/friend I lived with for a few years. He fills the tank and that is about as far as he goes to work on his car so for a month or so he kept telling me that he wanted me too take a look at his car as he had a rattle at 2200 rpms. Not 2100, not 2300, but at exactly 2200 - he kept telling me that for about a month I think when he thought about it. He normally only came home when the bars closed so the first day I was out in the driveway and he woke up at the crack of 11 he asked if I could take a look at it. He started the car and showed me and he was right, only at 2200 rpms.... So he pops his hood, as he goes to grab the prop-rod I tell him to stop, I see the problem. He is still holding the hood and now looking in confusion that I spotted it so quickly. I laughed my ass off as all it was, was the prop rod was not latched under the hold-down and you could see spots that it had rubbed through the paint from rattleing between the hood/core support. If he would have just popped the hood up and stuck his head under it a month ago he would have fixed it himself with out even knowing.
get under the dash and tighten up every screw/bolt you can see. Take some wire ties with you and tie up any loose wires that are hanging down. Grab/pull/tug on anything you can see too see if its loose and try to figure out a way to tighten it up. see if you can reach any loose wires or if the back of the deck is able to move by sticking your hand up into the dash by the accelerator and the glove box.
