  The connection between the accretion process that powers AGN and the
formation of jets is still poorly understood. Here we tackle this issue using
new, deep \chandra and \xmm observations of the cores of three powerful radio
loud quasars: 1136--135, 1150+497 (\chandra), and 0723+679 (\xmm), in the
redshift range $z$=0.3--0.8. These sources are known from our previous \chandra
snapshot survey to have kpc-scale X-ray jets. In 1136--135 and 1150+497,
evidence is found for the presence of diffuse thermal X-ray emission around the
cores, on scales of 40--50 kpc and with luminosity L$_{0.3-2 keV} \sim 10^{43}$
\lum, suggesting thermal emission from the host galaxy or a galaxy group. The
X-ray continua of the cores in the three sources are described by an
upward-curved (concave) broken power law, with photon indices $\Gamma_{soft}
\sim 1.8-2.1$ and $\Gamma_{hard} \sim 1.7$ below and above $\approx 2$ keV,
respectively. There is evidence for an unresolved \feka line with EW $\sim$ 70
eV in the three quasars. The Spectral Energy Distributions of the sources can
be well described by a mix of jet and disk emission, with the jet dominating
the radio and hard X-rays (via synchrotron and external Compton) and the disk
dominating the optical/UV through soft X-rays. The ratio of the jet-to-disk
powers is $\sim 1$, consistent with those derived for a number of gamma-ray
emitting blazars. This indicates that near equality of accretion and jet power
may be common in powerful radio-loud AGN.
