I forgot to mention this as I don't think its anything mechaniclly wrong with the car its just really annoying,its been doing it right along but it never got any louder so i thought nothing of it. I have a '94 deville 4.9 and when I'am acelerating sometimes I'll get a rattleing sound from under the car like its coming from under the middle of the car. I was thinking the cat converter's heat sheild maybe?,I had a lincoln towncar that did the same thing and sounded pretty much the same. Its just really annoying and I'am wondering what it could be any ideas?