RAYMR.... I am still having the exact same issue with my 85' 380SE and it seems to be getting worse.

Last time I drove it (Thursday afternoon), I had taken my mother to the post office and was in the car waiting for her. I left the engine on and left it in drive, so I would not have to deal with the stalling when I placed it in drive. Strangely it stalled out just as I let my foot off of the brake. It started right back up and went on. Before that when I stopped at the bank, I had turned it off. I restarted it and placed in drive and it stalled. It did this twice, then it finally went. This was around 3pm. The engine temperature was at 100*C. Later that evening, I drove it again around 8pm and it did perfectly, as the engine temperature was cooler. I had driven another car earlier in the day. I have 4 cars, but I enjoy driving this one and drive it despite the stalling, but I am about ready to stop driving it later in the day (or on that 2nd or 3rd trip out).

Sometimes my idle will drop to almost "0", yes "0", RPMS when I place it in gear, but it does not stall, but sometimes it does stall. Also, when hot, it idles at 900 rpms, but does not keep it from stalling. Its crazy. Sometimes when I get home, I will "test" it and place it in park, then drive and I cannot make it stall. Like yours, it stalls when it wants to and gives no warnings.

I also do not know it has stalled until like you said, the steering gets heavy. Sometimes mine also stalls when I make a turn into a parking space, or on the slow turns as I near my house. It is starting to get embarrasing, because the other day, it stalled at a traffic light. I was setting there for about 45 seconds, released the brake and it stalled as quickly as turning the ignition off. It started right back and I was on my way. It seems to be getting worse.

I am thinking it is the idle control valve, but now it seems to be linked with the brake pedal. Perhaps a vacuum leak is the problem with mine, but who knows with these cars?

Good luck to you. Hopefully we can get these cars back in proper working order.