Since you know the temperature sensor is out of spec (and by quite a lot) I'd change that to eliminate it as a possible problem.

When you changed your plugs, did you properly gap them? I had an instance helping a friend recently where .002 made the difference of the car stalling when hot and running perfectly. .040 was too wide, .038 was perfect (this car wasn't a Mercedes, just an example).

It's worth checking your fuel pump relay as well. They seem to have a reputation for failure due to bad solder joints. It's possible that the temperature is coincidental to the relay packing up or flicking on and off as you drive. If the fuel pressure goes south due to the pump not running properly, you can expect problems. The same goes for the OVP mentioned above, however you'll usually have signs it has problems in the cabin (warning lights on the dash for example)

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

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