Actually the needle stays pegged at 3 even after the car heats up in idle.
When I said sometimes it drops (between drives) I meant that I turn off the car and started again an hour later and the needle sometimes stays in the proper 1 bar range or sometimes jumps to the 3 bar.
In other words it still stays pegged at 3 after the car is warm and is in idle.
Thanks for the advice though you guys are very knowledgable.
I think that I'll just go ahead and chage the oil pressure sensor.
Could I still drive the car like this for anoth week or two before I fix the oil pressure sender...or is this dangerous?