One good way of determining plug wire condition is run the engine in a dark location (garage at night with the lights off for example) and looking for the light show aka arcing. This, combined with a good visual inspection and verification of proper resistance (sorry, don't know the spec for Volvo wires but for Audis it's 10k ohms I believe) will tell you if there is a problem or not. On the 850 you'll need to remove the little cover the wires pass under to do this inspection of course....
Cap and Rotor I tend to change pretty often, plug wires are more of an as-needed thing for me.
|