It's normal for oil pressure to fall as the engine warms-up, and its normal for it to increase with engine speed. A warm engine at idle will typically read about 1.5 bar.
Your oil pressure may actually be very low, Dave. Or you may have a faulty pressure sensor, cluster, or wiring between them.
You can test the wiring and cluster easily yourself. If you unplug the sensor (picture) and connect 150-ohms of resistance to the leads in its place, the pressure gauge on the cluster should read 3 bar (key on, engine off). If it reads significantly lower, wiring or cluster are faulty and further tests are indicated. If it reads okay, you ought to have the oil pressure checked at a shop. They should have an external gauge which they can connect to the engine for this.
Your oil pressure may actually be very low, Dave. Or you may have a faulty pressure sensor, cluster, or wiring between them.
You can test the wiring and cluster easily yourself. If you unplug the sensor (picture) and connect 150-ohms of resistance to the leads in its place, the pressure gauge on the cluster should read 3 bar (key on, engine off). If it reads significantly lower, wiring or cluster are faulty and further tests are indicated. If it reads okay, you ought to have the oil pressure checked at a shop. They should have an external gauge which they can connect to the engine for this.