Weird oil pressure guage problem on 190e

Can anyone help? I have a 1990 Merc 190e auto which always runs beautifully. However, the reading on the oil pressure gauge occasionally 'bounces' around and will sometimes show no reading at
all. HOWEVER....when I press the trip meter reset button a couple of times (I did this originally to see how far I was driving with 'low' pressure), the gauge suddenly springs to life and reads a very healthy 3.0 dropping to around 2.5 when idling. Sounds like a wiring problem rather than sender unit, but has anyone else ever experienced this? If so, what is the solution?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I'd certainly suspect an electrical connection problem in the instrument cluster or oil gauge unit, not a problem within the motor.
--
2007 T.G.Lambach. Publication in any form requires prior written
permission.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It may be as simple as a fuse, or sending unit or as complex as a bad connection/cracked printed circuit board in the instrument panel.
Based on my experiences with the 126 chassis, I would replace the fuses with new copper ended fuses. My instrument panel used to act up in different ways when the breaks were applied with the lights and fan on due to poor fuse connections in the fuse box.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I kinda agree on the fuse... just replace the fuse and see if it helps.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.