Review on Autolite XP5363 Iridium Spark Plug by James Hardy

The spark plugs were sent in an envelope. Four of the six spark plugs were removed from the individual boxes in which they were packed. Other boxes were smashed and partially or fully opened due to being broken in the padded shipping envelope. Was the insulation damaged by an impact and the porcelain-like insulation collided? Hard to say. To prevent this, it is desirable to pack better. On some vehicles, replacing spark plugs is a tedious job, so installing defective spark plugs can result in a significant increase in uptime.