  We investigate the effects of the multielectron polarization of the ion
described by the induced dipole potential in photoelectron momentum
distributions produced in ionization of the CO molecule by a strong laser
field. We present results of the numerical solution of the time-dependent
Schr\"{o}dinger equation in three spatial dimensions and semiclassical
simulations accounting for quantum interference. We predict the change of the
asymmetry and interference patterns in two-dimensional photoelectron momentum
distributions as well as longitudinal momentum distributions. By using a
semiclassical model we identify the mechanism responsible for the observed
effects. It is shown that the modifications of electron momentum distributions
are caused by a combined effect of the force acting on photoelectrons due to
the induced dipole potential and the linear Stark-shift of the ionization
potential.
