At what RPM's should my car idle - 1991 745 Turbo? It currently idles at 600, stays consistent through A/C, etc., but goes up when returned to Park after a drive (up as high as 1100, but usually just up to around 800).

I have replaced a few sensors and other stuff (TPS, IAC motor, engine temp sensor) but no change. Cleaned the throttle body and readjusted the throttle linkage and throttle position switch (yes, it clicks when it is supposed to). Checked all vacuum hoses and they were fine. Negative crankcase pressure (vacuum) fine, oil breather box accepts oil readily (flows right through when I pour some in through a funnel), cleaned the turbo CBV, etc.! Could it be the O2 sensor?

The oil pressure light comes on at idle when the car is fully warmed up (when it has been on the highway, esp.) but nothing ever causes the car to stall. If I didn't know much about these cars I would say everything is fine, except for the oil pressure light, but I want to get this taken care of.

I have gotten some good suggestions before from you about this, but I thought I would throw my line in one more time. Thanks a lot everyone.
--
Darius in Albany NY '86 744 GLE (172K); '91 745T (161K)