Replacement RED silicone insulator boot only for popular ignition coil 30713416 .
That coil is commonly found on S70, V70, S60, S80, XC70, XC90,
The coil insulator boots get exposed to extremely high temperature. With time they stop their function as an insulator between the engine and the ignition coil, Ignition spark that is generated by the coil will jump the gap between the cylinder head and the ignition coil causing engine misfire. If there is and issue with the the PCV system of the engine, the insulators get soaked with the engine oil accumulated under the spark plug valley cover.
You can solve the misfire mystery by installing the
replacement boot only.