A leak down test will not give you an indication of bad valve stem seals. You may be able to check for a bad valve seal at the seat. That's a bad valve which would cause a dead miss, not a puff of smoke on restarts.

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1984 280SEL, 62,000 miles
Euro model in the USA
1983 300D (Totaled out 10/2004)
New Factory Mint Green paint
Palomino int
1982 240D (Steak dinner for two)