I've got a 2003 Kia Rio (4 cyl) that started shuddering on me yesterday. When I got home I found that the cylinder 3 spark plug wire had gone bad. Sparks were coming out the side at an apparent insolation leak rather than out the bottom to the spark plugs. I replaced wire 3 with an old one I had lying around. Took it for a test drive and all seemed fine.

Now one day later, severe shuddering starts up again. Its the same failure but in the cylinder 1 wire! Sparks coming out the side. Replaced it and again things seem okay.

Is this just a coincidence that two wires would go out independently 2 days apart? They're from the same original set and are 20k miles and 3 years old.

Any ideas what is the likely cause? Coincidence or something more sinister (i.e. expensive)?

1 Answer 1


The plug wires all tend to have the same age and have suffered the same conditions. As the insulation gets dirty, then it becomes more susceptible to moisture and subsequent breakdown.

Whenever I have had one breakdown I have always replaced the complete set.

Replacing one was always a "get you home" measure.

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