The secondary alarm circuit kicks in at 2000 rpm -- clearly your sender is
indicating low pressure right then, but the alarm goes away with rising
pressure as rpm continue to rise.  My first guess is sender going bad, they
tend to fail progressively.  Not the one btw the pushrod tubes, the other one.

d

At 08:16 PM 3/2/2000 , Chuck Kuecker wrote:
>I have had a strange problem develop on my '91. At a narrow range around
>2000 RPM, the oil pressure warning light and buzzer come on. Above and
>below this range there is no problem. As soon as the street parking
>restrictions are lifted around here, I plan on replacing both oil pressure
>switches. Just wondered if anyone has seen a similar problem. At first I
>thought it might be an intermittent pinched wire, but the wiring harness is
>in good shape.

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"