  (abridged) This is the second paper presenting the results of two years of
monitoring of GRS 1915+105 with \integral and \rxte and the Ryle Telescope. We
present the X-ray spectral and temporal analysis of four observations which
showed strong radio to X-ray correlations. During one observation GRS 1915+105
was in a steady state, while during the three others it showed cycles of X-ray
dips and spikes (followed by radio flares). We present the time-resolved
spectroscopy of these cyclesand show that in all cases the hard X-ray component
(the Comptonized emission from a coronal medium) is suppressed in coincidence
with a soft X-ray spike that ends the cycle. We interpret these results as
evidence that the soft X-ray spike is the trigger of the ejection, and that the
ejected medium is the coronal material. In the steady state observation, the
X-ray spectrum is indicative of the hard-intermediate state, with the presence
of a relatively strong emission at 15 GHz. The X-ray spectra are the sum of a
Comptonized component and an extra power law extending to energies >200 keV
without any evidence for a cut-off. We observe a possible correlation of the
radio flux with that of the power law component, which may indicate that we see
direct emission from the jet at hard X-ray energies. We study the energy
dependence of a ~4 Hz QPO during the hard-intermediate state observation. The
QPO-``spectrum'' is well modeled by a power law with a cut-off at an energy
about 11 keV that clearly differs from the relative contribution of the
Comptonized component to the overall flux. This may rule out models of global
oscillations of the Compton corona.
