Odd behaviour from oil pressure gauge

[Error404]

This a new one on me!
My oil pressure gauge is behaving pretty strangely. With ignition on it immediately jumps to 2bar, then stays there without a flicker while engine starts & runs. The gauge has never read more than 4bar since I can remember, but it goes straight off the scale if i reverse the wires on the sender so its not sticking or anything. The sender is relatively new, but I tried another one today and got the same result.
So before I try and find a new one, is there anything other than the gauge itself which could be faulty and causing this?

Cheers
Alex

[Sleeper_Avant]

surely you have some resistance values in some literature you can use to check?

just a thaught before spensing any cash

[Error404]

yes that woud be useful if anyone can help?

[mrtat2k9]

Im assuming its a s2 i had one the other week where the aux plugs where the problem sprayed them with contact cleaner and been fine ever since

[Error404]

its a cq20v but they are S2 gauges. I'll give that a try

[mrtat2k9]

i think that has one big plug dont it next to the lambda plugs.