I am getting only about 13 mpg in my newly acquired Outback and am new
to diagnosing these problems and need a little help with where to go
without replacing everything.  I did a OBDII read and exported the
data to Excel :
Test was initiated beginning at idle with engine warm (coolant temp
reads 180-190 deg F).  Idled for 1:34  (1 minute,  sec)and the
increased rpm to ca. 2000 rpms for about a1.5 minutes and then dropped
rpms back to idle.

Mass Air Flow Sensor :  Seems fine throughout the test reading steady
at idle (0.4-0.45 lbs/sec) and increased (2000) rpms (1.0-1.15 lbs/
sec).

Timing Advance for Cylinder 1:  15 deg at idle and 44 deg at 2000 rpm
(steady on both)

Short Term Fuel Trim:  -25% at idle and increase in rpm, but up to 0%
when rpms went from 2000 back to idle and fell gentle and steadily
back down to -25%.  Seems I'm running rich, but why?

Long Term Fuel Trim:  Fluctuating from 26% to 27% at idle and constant
at 27% at 2000 rpm

Intake Manifold Absolute Pressure: 4psi to 4.5psi at idle and decrease
to 3.5 at 2000 rpm

Upstream Oxygen Sensor Voltage:   Varies from 0-0.4v, but moreover 0.2
to 0.4v.  It did increase to 0.5 after going from high rpm back to
idle and then drop back to previous levels once at idle

Downstream Oxygen Sensor Voltage:  Almost the same as the upstream O2
sensor, but about a 0.1v lower and looks like it had a time lag of 2-3
seconds.  Does this mean my catalytic converter is shot?

Upstream Oxygen Sensor Fuel Trim: At -22% to -25% except when rpms
drop from 2000 to idle and then it jumps up to -1.5% and then steadily
decrease back to -25% in about 1.5 minutes

Downstream Oxygen Sensor Fuel Trim: Always at 0.  I'm guessing that
the car just doesn't register that parameter.

If I can find out how and where to post the charts, I will ( I can do
it in PDF, Excel, or Word)

Thanks in advance....

Sparky