If it sounds like squeaky bed springs then my money is on the swaybar bushings.

Here's the thread Moncha started way-back-when with the part numbers, you can get 'em from Autozone.com or most anywhere that carries Energy Suspension products: http://www.vehicross.info/forums/sho...rgy+suspension

From the thread:

Energy Suspension

Front: 9.5163G Greasable Sway Bar Bushing Set 28MM

Rear: 9.5156G Greasable Sway Bar Bushing Set 3/4” 19MM