My SL stalls on me , so frustrating and scary in traffic, I had a 91 300E that would do that, replaced tons of parts, still did it, turned out to be the dist rotor was bent a tiny bit, when it heated up it it would bend more and lose proper position killing spark, then bend back when cooled and all OK.

with my SL it is random stalling, didn't know if it was fuel or electrical, finally bought a cig lighter plug in Volt meter, cheap $16, Autohauz AZ has it, found my voltage was going below 12 volts killing power to modules , those can't run on low voltage and car dies, bought new alternator/ voltage regulator, better but still stalling, pretty sure its my ignition switch now causing issue, good luck.

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John