1993 Lincoln Town Car new shocks but car sits low

Maybe a weak/sagged coil springs

A common mistake, shocks do not help hold a car up. Only absorb shock. Mechanics love to sell them though, and often times they're needed to correct uneven tire wear or harsh or bouncy ride. I think your problem lies in the air ride system. Do you hear the pump run when you turn your key on? You should hear a low rumbling noise under hood near air cleaner housing. This pump should quickly inflate the system then cut off in a few seconds.