There have been, in earlier forums, a question about which plug to use in different year Opti's. I asked the question of the NGK technical plug guy.
On the NGK site the 1998-2002 225 opti requires a PZFR5F-11 gapped at .040. The 2006 225 opti (No other year is mentioned.) calls for the IZFR5G gapped at .031.
The tech guy says: Both plugs are physically the same. The only difference is the set gap and that one is iridium (IZ) and the other is platinum.
The tech guy also says: The opti requries the larger plug gap of .040 whichever plug is used. He cautions: Be careful not to put pressure on the fine wire central electrode. The gap should be changed by only moving the ground electrode.
So there you have it - for those who might be interested - from the source.
On the NGK site the 1998-2002 225 opti requires a PZFR5F-11 gapped at .040. The 2006 225 opti (No other year is mentioned.) calls for the IZFR5G gapped at .031.
The tech guy says: Both plugs are physically the same. The only difference is the set gap and that one is iridium (IZ) and the other is platinum.
The tech guy also says: The opti requries the larger plug gap of .040 whichever plug is used. He cautions: Be careful not to put pressure on the fine wire central electrode. The gap should be changed by only moving the ground electrode.
So there you have it - for those who might be interested - from the source.