Hi all,
Briefly, car [1995 S-420, 88k] overheated - suspected closed thermostat. Had heads done, new thermostat and new head gaskets.
Car idles very roughly, worse when warm. Temperature is normal on highway and in town. Also appears to run ok at increased revs or normal driving speeds. No apparent stumbling or vibration.
The oil pressure is around the "3" mark when cold, and during normal driving drops to 2 - 2.5. However, when stopped and idling the pressure falls below "1". This could just be due to the grade of oil used [I'm checking to see what was used], or something more serious.
My mechanic suspects the idle problem to be related to the O-2 sensors, and wants to replace them next. He's checked for vacuum leaks, etc.

Would appreciate any thoughts on possible causes of idle problem, or if something was missed during the engine work.