My 91 had the self leveling suspension all the way around. You can tell, if
you look at the front strut thru the wheel well and you se a bunch of wires
all going to a plug on the side of the strut. This plug is an electic
solonoid that activates the strut
I recently replaced mine with a conventionl strut system from a New Yorker.
The only place that you can buy replacement air struts is from your local
Chrysler dealer and the are in the range of $900 apiece.
Bob
91 Imperial