I'm a new owner of a 93' 190e 2.6.
I've noticed that as soon as turn on the car the oil pressure rises to the max 3.0 bar and simply stays there. I sort of recall this being a recent phenomenon (I've only had the car 1 month).
I've read that the oil pressure should be between the 1.0 and 1.5 bar at idle.
The car does not drive hot and the oil looks clean. According to the next oil change sticker placed by the dealer, I should still have 1,000 miles left on this oil change.