Check the Vehicle Emission Control Information ( VECI ) decal located in the
front of the engine compartment ( it will show what type of spark plugs to
use and the spark plug gap )
the best spark plugs for all ford vehicles are the motorcraft type, which they come from ford.
Motorcraft AGSF-34EE
Motorcraft is best for Ford
Ford uses Motorcraft Spark Plugs
MotorCraft
I used factory plugs MotorCraft...
Ford uses Motorcraft Spark plugs on all there vehicles.
Make sure you are using Ford OEM (Motorcraft is not always OEM) Spark Plugs that are designed for you explorer.
Motorcraft spark plugs are a factory ford part. Any ford dealer would have them. They are also avaible at most parts stores. They should carry several brands in stock. Advanced Auto has many sizes in stock, or can get them overnight
motorcraft plugs are always the best in a ford any cheep ones
For a 2006 I just paid $11.00 a piece. Ford motorcraft.
.044 inch ( according to motorcraft . com )