The key to this discussion is the amount of resistance -- if you get wires and plugs matched to give the correct amount, platinums work fine. If not, you have trouble from excessive resistance and weak spark.

The only thing I've not had trouble with on the 280 is the platinum plugs -- I also have plain (non resistance) wires.

The O2 sensor not connected (or shorted with the heater wires, or a bad heater wire, whichever it was) probably carbon fouled the plugs. A few days driving will clear them and you will be fine.

I put Platinum +4s in the TE, they run just exactly like the Champion single electrode plugs I tested when looking for running problems (that eventually turned out to be a bad fuel pump relay).

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!