Had the same situation; turned out to be a short - broken insulation on low pressure switch wire. 

Karl Wolz
Sent from my electronic umbilicus

On Oct 18, 2011, at 1:13 PM, Loren Busch <starwagen@GMAIL.COM> wrote:

> Got a mystery (and hopefully not a major problem) going on with my '90 Westy
> (stock 2.1L and automatic).  Driving home from a VW event Sunday I suddenly
> had a flickering oil light while cruising at about 50 mph.  No buzzer. Came
> and went over the next few miles.  I pulled over and checked the oil level,
> down about 1/2 quart but still well above the lower mark.  Added 1/2 quart
> and continued home.  Blinking/flickering continued for about a mile then
> quit the last two or three miles getting home.  Drove it today in town, no
> blinking light first half of trip then started again.  And it doesn't seem
> to bear much of any relationship to RPM, doing it at cruising speed above 2k
> and about the same at idle.  I've had oil lights coming on in my '85 (stock
> 1.9L) when the wrong oil was put in once or when very hot.  But that was
> always a steady light at idle, went away at higher RPMs.  This is not
> steady, just flickering.  BTW, I know that the oil pressure sensing setup is
> different in the 2.1L vs. the 1.9L.
> I guessing (hoping?) that it's a loose wire connection or bad pressure
> sensor.  Which of the two sensors, high or low, would most likely cause this
> kind of behavior?
> I'm taking the van into my mechanic Thursday morning to try to pin this down
> (and hope it's something short of an engine on it's last legs) but asking
> the lists for any hints.