Without knowing if they have ever been replaced I think it's a good suggestion for a 12 year old vehicle to replace the plug wires, they do wear out over time and can be a cause of misfires

 

Inductive coupling reminds me of transformers, though transformers are a/c. A better insulator should prevent the magnetic field which causes inductive coupling.

 

Insulation has squat to do with it. Hold a magnet against one face of a pane of glass, and put a ferrous metal on the other face. It'll stick.

You don't need alternating current to inductively couple; switched DC will do it just fine, and of course that's exactly what happens inside your ignition coil -- and will happen if you have old, tired, and/or cheap spark plug wires, too.

 

I had a set of 8MM accels and was getting a bad miss at random. Further and CLOSE inspection made me see a spark plug wire that was hitting my header. It burned the wire and it was cracked, just a bit, where the wire was hitting the header. I had an extra wire and used that until my next tune up.

you can just use a zip tie to keep the wire away from whatever it is hitting and you can buy yourself some time. I did that with my camaro in 2001. The spark plug wires were laying on the headers and about 3 were burned.

I am gonna get magnecor wires and pusltar plugs around april timeframe, before my move. I will let you guys know how they run. I have heard nothing but great things from credible sources.

 

I've got the DUI Live Wires, great humongous fat bastards they are (10mm inside a braid), and just let them fall where they fell without any effort given to routing them. They won't fit into the factory looms anyway. No cross-fire or misfires, no problems at all -- with the DUI Screamin' Demon coil pumping NGK Iridiums gapped at .052" so the voltage is certainly getting up there into the big numbers.

Good plug wires can make all the difference in the world. I don't suppose a stock ignition would require 10mm wires, but installing the cheapies is risking finding out the hard way about false economy.

 

Well, I've never dissected a plug wire, but I am pretty sure that it contains some form of magnetic shielding (i.e. insulation). Even the coaxial cables you use in your house contain shielding.