  We investigate the inelastic hard disk gas sheared by two parallel bumpy
walls (Couette-flow). In our molecular dynamic simulations we found a
sensitivity to the asymmetries of the initial condition of the particle places
and velocities and an asymmetric stationary state, where the deviation from
(anti)symmetric hydrodynamic fields is stronger as the normal restitution
coefficient decreases. For the better understanding of this sensitivity we
carried out a linear stability analysis of the former kinetic theoretical
solution [Jenkins and Richman: J. Fluid. Mech. {\bf 171} (1986)] and found it
to be unstable. The effect of this asymmetry on the self-diffusion coefficient
is also discussed.
