PEH, your 1980 300SD also does not have the afterglow feature. I'm pretty sure the 92 does have it, and plugs just don't last as long on afterglow equipped engines. Keep that in mind when you tell people to replace only one plug.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
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