Originally posted by lauraq:
I put in the Bosch Platinums +4 bought at Canadian Tire last summer. I have had no problems with them. Are these other ones you are talking about better or something? Just wondering.
There was discussion about the +4's collapsing, due to the reverse firing of the Duratec ignition system. That is to say that the plugs fire from the ground to the centre electrode, necessitating platinum on both ends. This is what I was reading in the Performance Forums. Needless to say, I pulled my + 4's, out of curiousity, and replaced them with Motorcraft double platinum plugs. Upon observation of the +4 plugs, they were in excellent shape, knowing how many km's were put on them by the previous owner of my SVT combined with the mileage I have put on, uumm, very little.
That said, I don't see any problems using the + 4 plugs, now seeing my own plugs. One thing though, they were quite black, verifying that the SVT computer likes to run the motor rich.
