84 chassis, Digifant inline in the diesel style..
  I have what I'm guessing is the stock instrument-pod in my inline VW
van...no tach and no buzzers....  It just began showing lower than normal,
and incorrect readings, twice yesterday on startup,  both the fuel gauge
and the coolant temperature gauge.  Then they are right again.... Dunno if
they creep back up, or correct themselves after the next start up.... can't
safely watch their behavior long enough to see, but one episode they stayed
low for a 50 mile trip...   The fuel should have read full, but after just
35mi it was below the odd VW idea of 3/4 tank...and the temperature reading
was just off dead cold when it normally reads just below the top of that
two line zone they put at the left end...When loaded and flogging it, the
temp gauge normally gets up to the led in the center.  In cruise mode, this
van indicates about halfway between the led and that lower, what must be
the Teutonic warm-up zone...
   So both those gauges were reading too low for what was really there, in
reality.... I double check the temp always with my oil temp and the
alternator lite...
My low coolant light has never worked...and before  get "scolded" for
that.... I don't care about that...
   Any how, is there a common ground, or perhaps an intermittent resistor
that may be sometimes causing those two gauges to give lower than normal
readings, and then be right again, sometimes? Thanks if anyone has any
ideas..