1 bar oil pressure at idle is good. You should hit 3 bar once the rpms get around 1,500. Sounds to me like your oil pressure is fine.
Rough idle. My experience points to spark plugs and their gap. A gap of .040 idles smoother than .032 in my case. Ensure that spark plugs wires are secured. You may need to take a look at the condition of the rotor and distributor cap.
Then of course there's the FUEL side of the equation and the possibilities there are endless.
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.