My 300e developed sluggish response from a full stop, and limited power going up hills. I pulled a plug, and discovered not bosch plugs but these ac delco, one of which was obviously gapped too wide. Pulled them all and found one with a long crack along the plastic insulator, apparently shorting out the plug so the engine was working on only 5 cylinders. Replaced with lightly worn bosch non-resistors from the parts car. Feels like a new car.

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87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)