This is quite interesting. I have a similar problem, but i can narrow mine down. Its kinda funny actually. When it rains, i guess since my motor mounts are so crappy, the engine and tranny literally move and cause the whole car the vibrate anytime im on the gas or letting the engine come down the rpm range. I have to be on the gas just slightly in order to keep it from shaking really bad. How are your motor mounts? I can feel my engine and tranny nowadays also move and it feels like the wheels are going to fall off. But its just the motor shifting around. Kinda scary, but it stays put most of the times. and you know when its where its suppose to be.
James
