We left today in our 1985 1.9L Westfalia for a one week camping trip when
about a hour from home in Interstate traffic the oil pressure lamp started
flickering.  I pulled over and checked the oil.  If anything it was over
the full mark.  The engine sounded fine so i took back roads to get home.
 The light stayed off at slow speeds or stop and go traffic, but at
sustained speeds above 45 or 50 it would flicker, sometimes quickly and
other times slowly on and off.

The Castrol 20W50 oil only has about 1,500 miles on it, but it's been 6
months since it was changed.  I'm changing it now.

My question is, can there be a problem with low oil pressure if the light
stays off at low RPM?  From what I've read, it seem like when oil pressure
is low the light is more likely to come on when the engine is idling, not
when it's running at 50-60 MPH.  The engine is VW rebuilt 8 years ago with
54,000 miles on it.

Besides the oil change, the only other thing I can think of is to check the
wiring at the sending unit when the engine cools down.  Is there anything
else I can do before we try to leave again?