Hey guys:

Question: when my 560SEL is cold, it requires a few cranks before it kicks over, and has a resulting cloud of blue/white smoke that quickly dissipates after ignition. The car runs a little rough for five or ten minutes until it warms up, typically with a little rough and lowish idle. The car then runs pretty smooth and nice, and when it's warmed up, it doesn't have the smoke/hard start issue at all.

I am certain y'all will have a good idea what is causing this; thanks in advance for ideas I can troubleshoot.

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1990 MB 560 SEL
1985 MB 300D (r.i.p)
1999 Audi A4