A $3$-dimensional compact manifold of negative sectional curvature admits (by geometrisation?) a metric of curvature $-1$, and so its fundamental group has subgroups of finite index. I wonder if an analagous question is open already in dimension $4$ -- i.e. it is not known that $M^4$ with negative sectional curvature always have a cover of finite degree? Are there any positive results in this direction?
This a folow up to question that turned up to be open http://mathoverflow.net/questions/40120/existence-of-finite-index-torsion-free-subgroups-of-hyperbolic-groups