i will try and explain this as best i can, as i dont have a picture of my oil gauge to put up. hoefully anyone with an ef wil know what im talking about!
my car usually runs good oil pressure-the needle sits on the 3rd white bar from the bottom (2nd from the top).
but this arvo when i was goin down my driveway i had it at low revs and the needle was sitting on the 2nd white bar (the middle one)
so i kept an eye on it as i took off down my street, the pressure went up, but stil wasnt as high as normal-sitting a bit below what it normally does, but not by much.
i kept an eye on it while i was driving and it stayed the same, until i pulled up and i looked at it while it was idling-it was sitting on the 1st bar from the bottom.
im not sure if my gauge is faulty or what but it seems that the lower the revs the lower the pressure. can anyone make sense of my descripion and shed some light on this as i am scared to drive it home!

a common problem on these is a bad earth causing incorrect pressure reading

How do you fix this? Where's the earth? My car does much the same, but the low pressure warning buzzer actually goes off if I drive for long enough...