the oems are platinum because ford uses a wasted spark ignition system .... dont put coppers in there... use platinum motorcraft. not bosche either they are very shitty and the iridiums are junk

they are brown because they are burning on the exhaust stoke when the exhasut valve is open......the copper cores run like shit.

i used them on my svt cobra when i was spraying and had all sorts of problems with them....... bad thing is. copper cores are recomended with nitrous...... and platinums are not...so much....

copper cores are getting hot as fuck because the electrode is so big....and they are creating resistance in your ignition coil pack.....

get new plugs and wires and youll be good