I have been having an intermittent idle problem; it jumps up and down between 600 and 2000 RPM. It will also stall, sometimes even coasting to a stop. It was so bad it would stall after running only one mile. I changed the fuel pump relay (with rebuilt) and it seemed to go away but when it really warms up (about 90-95 C) it will act up again. When it is warming up, and warms up, it runs perfectly and idles so smooth and quiet that I have to look at the tach to be sure it’s running. In city traffic the temp goes to 90-95 C and the problem appears. If I get on the highway or just go without a stop, and the temp drops to about 80-85 C, it goes away. Seems to be linked to the temperature. Any ideas?

Steve
1985 SL500 (Euro) (With Lambda system)