Review on Denso 3289 Spark Plug: Optimum Performance and Durability for Your Vehicle by Marcus Chavva

Purchased 6 pcs in November 2006 to replace badly worn stock spark plugs with a gap of 2.5mm. It is very important to provide these plugs with an anti-seize coating to make them easier to remove when replacing them, especially after such a long service life. I replaced these spark plugs in February 2014 after 151,000 km (94,000 miles). Before the replacement I had very good mileage, no misfires and the truck started fine. The color of all plug electrodes was a pleasant light brown. The wear of the center electrode was significant. I estimate that the electrode diameter is 60% of the diameter of the new Denso PK16TR11 connectors I installed.