The cap fits on the spark plug and connects it to the high-voltage wire, delivering the high-voltage pulse. This item is marked as a tuning part.
Replace it if the body is cracked, the contacts are oxidized, there is arcing and misfires, especially in damp weather. Check that the wire fits tightly into the cap and the cap onto the plug. Choose the part by the name and dimensions on the product page and compare it with the original.
