Hey guys new guy here just picked up a 2008 Dakota 4.7. Right now I'm fighting a cylinder 8 misfire. It has a new coil on that's cylinder (dealer put it on after the check engine light came on) but the light came back on. The light only comes on, on first start up in the morning usually when it's cold or damp outside. The truck has 94k on it and I pretty sure the plugs have never been changed. I see that people go a step colder on the plugs (auto lite 3923). Does everyone change all 16 plugs to that? I know the secondary plugs are a different plug from the main. Thanks for your help.

 

This engine uses TWO DIFFERENT types of spark plugs. A total of 16 plugs are used. The plugs are mounted in two rows (banks). The upper row (5) is used on the intake valve side of the cylinder head. The lower row (6) is used on the exhaust valve side of the cylinder head. The upper row (5) uses Bosch Nickel Yttrium plugs. The lower row (6) uses Bosch Iridium plugs. DO NOT INTERCHANGE THESE PLUGS.

straight from a Dodge Tech