90 300SE 110K mi stalls at idle after 5 min, then ok after 10

The car starts and runs fine for about 5 minutes then stalls at every stop. After 15 minutes or when completely warmed up, it runs fine. The stalling out is frustrating and dangerous as I am usually just pulling into a busy highway at the stalling point.
Any suggestions on what it might be?

test the idle stop switch, make sure the overvoltage protection relay is good, what is the o2 sensor doing, fuel pressure, is it loosing spark? . lots of stuff that could cause this. unplug the EHA and see if it changes anything.

test the idle stop switch, make sure the overvoltage protection relay is good, what is the o2 sensor doing, fuel pressure, is it loosing spark? . lots of stuff that could cause this. unplug the EHA and see if it changes anything.

Thanks for the reply.
I know the spark is good, but I don't know about the other items. Where/what is the EHA. I have a cd manual that has schematics etc, but I can't look these things up as to where they are. Can you point me to where I can get better information.
I'm suspecting the fuel pump because when the car sits for a few days, it takes for ever to start. I changed the fuel filter and it didn't help.