  A study is made of the nonlinear dynamics of dual pumped microresonator Kerr
frequency combs described by a driven and damped nonlinear Schr\"odinger
equation, with an additional degree of freedom in the form of the modulation
frequency. A truncated four wave model is derived for the pump modes and the
dominant sideband pair which is found to be able to describe much of the
essential dynamical behaviour of the full equation. The stability of stationary
states within the four wave model is investigated and numerical simulations are
made to demonstrate that a large range of solutions, including cavity solitons,
are possible beyond previously considered low intensity patterns.
