My 3.4L V6 calls for using Double Ground Plugs-in the owners manual-and under the hood.
The auto shops list Iridium and Platinum plugs for this engine that are only single ground.
I want to upgrade to a better and longer life plug-but dont know if I have many options. NGK makes a platinum post only- double ground plug. Nobody seems to make a platinum-platinum double ground. And the NGK Iridium is only single ground.
Why the big deal over double ground ? I thought that was only important when considering coffee.