I had that problem, not really a fishtail but the rear end seem to be really loose. The problem went away after replace the rear struts.
Replace axle on 2001 buick Lesabre
The 2001 Buick LeSabre's fuel tank holds 18.5 gallons as found on http://consumerguideauto.howstuffworks.com/2001-buick-lesabre-3.htm
where is the pcv valve located on a 2001 buick lesabre
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Cost on replacing ball joints on a 2001 Buick lesabre
The PCV valve for a 2001 Buick LeSabre is located in the top of one of the valve covers. It is a plug in unit and is easily changed.
its under the back seat
6x9
What size speakers go on the rear of a 2001 Buick lesaber
It has a chain.
The battery is located under the rear seat cushion on your 2001 Buick Lesabre.
The socket size for the trunk tail light on a 2001 Buick LeSabre is 7mm. Bulbs can be purchased at most local automotive repair stores.