Originally posted by Tiger
I thought the double plats were required aftermarket cause the plugs fire electrode to ground on 4 and ground to electrode on the other 4. Isn't that why the manual says when removing plugs if you put the old plugs back you gotta keep em in the same cylinder? and there are two different plug numbers used.
Clarification please KY
For the 4.6L, you are correct. Use double plats or 4 of your plugs will still be worn out in 12k miles. From the factory, Ford supplies two different single platinum plugs, one that has a platinum electrode and the other a platinum ground. For service, Ford recommends replacing them all with double plats.