Many LeSabre models come with electronic suspension. Does yours have that? You also mentioned that all shocks and struts have been replaced? Were they the same with the original? If not, can you provide the brand and model?
The reason I ask is that I, at one time, replaced electronically controlled rear shocks with standard gas shocks per the driver's request. Three days later, he came back asking for the $700 replacement (the gas option was $130). He said the rear was bouncy and made a lot of racket.
Another thing to check is the rear ball joints, control arms and sway bar. The control arms and sway bar do have replaceable bushings.
Sunday, March 1st, 2009 AT 9:10 PM