I read OEM was Bosch or NGK for the US market and Bosch or Beru for the German. Autolite copper came out of this one (obviously not OE) but it was not misfiring either.
It doesn't matter now, without some real live data its all guess work as to what the real problem was with them.
I am interested only because it had a misfire that only got worse, it didn't start with the Bosch.
Originally Posted By: OP
003 ford f150 with a 4.2 liter engine.It had slight misfire at load .It seemed to be worse when it rained.Replayed plugs,coil and wires.It has one coil pack for all cylinders.Now the misfire is much worse used bosch Iridium plugs could that cause an increased misfire?