what rattels, eye balls. foot, tires, wheels, body panels, what? steering jerks , pedal>? do tell, what.
mine too , as my geriatric legs are like noodles.
foot brakes, hand brake?
moving or not.?
if moving , that ABS. your car have ABS?
some cars have early ABS back to 1991. ( junky design until 1996)
in general.
listed here as has them.
http://www.edmunds.com/nissan/altima/1994/features-specs.html
so is this your first ABS car??
or first time stopping on slippery surfaces with ABS
then its normal.
Brakes are dead serious.
get it road tested by any ASE mech,shop.
and win.