It may well be your ICU. They get Cold Solder Joints. I futzed with a bad/no idle and stalls. Cleaned the ICV twice with no results, replaced the OVP with no results, then bought a used ICU and VOILA! It fixed it and it has idled and not stalled for almost 2,000 miles.
I just happened to noticed that when my car did idle it was high, then would cut out or drop too low. I rapped on the ICU and it died. Thinking it may be a coincidence, I started up , it idled high, I rapped on the ICU and it cut out again. Did it two more times with the same result. Got a used ICU off Ebay and it purred. Have not resoldered the original ICU yet, but it is on the list.

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1986 Euro 500SEC "RUF" 9:1CR, "Rose"
1985 Euro 500SEC Cabriolet AMG Widebody
1982 Euro 500SEL "Blue"
2001 Texas Heeler (Aussie/Queensland X) "Sulphie",
2012 Queensland Red Heeler "Squeak"
Best dogs I've ever had.