I have an Air Pot sensor on the side of the fuel distributor - haven't checked it. I have looked and looked and looked for vacuum issues...can't find anything. Plugs were replaced - probably 2 years/15K miles ago - regular Bosch plugs. Pulled a few recently and they looked fine...

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE