Low oil pressure reading HELP !

[carluk66]

I have a Toyota hilux surf 3L TD Auto 1995 model. At idle the oil pressure reading is on the minimum mark and slightly higher when cruising yet while accelerating the needle on the gauge rises up but not above halfway on the gauge then settles down to the minimum mark... is this a common thing or problems with the oil pressure switch ? or is there a pressure release valve that would need replacing ?
I previously had a 1993 2.4l hilux surf and never noticed this happening on this models gauge.
ANY HELP WOULD BE GRATELY APPRECIATED PLEASE !

[NiftyNev]

When was the last oil and filter change?

Nev

[Gizmo]

If the gauage is dropping at constant velocity then something is wrong.....on idle the oil pressure gauge shows on minimum mark...on acceleration gauge goes up and around constant velocity [throughout the range] the gauge stays on or around halfway mark.

[carluk66]

To answer Nev , the oil and filter was changed last week.
To answer Gizmo, it does drop to around miinimum on constant velocity .
Any suggestions ? thanks in advance.

[BUSHWHACKER]

If you're using synthetic or semi-synthetic oil, that will make the pressure gauge read lower than normal.


Here's some pics of the gauges....

http://www.toyotasurf.asn.au/techsite/gauges.htm