Damp Weather no start
 

My 86 420sel will not start in rainy or damp weather. I had a radiator leak at the top hose and after that this started. I have pulled just about all the connections I can find and cleaned them, after the car sits and the weather warms it will start first hit of the key and run smooth.

Spray the ignition components/wires w/WD/40 and wait 10 min....then try it.

I'm willing to bet it's the coil. Check for corrosion where the plug wire lead attaches to the coil...