is it always necessary to change the spark plug wires? i know it's good..but is it a must?

It depends on how you define "must". New sparkplug wires (as opposed to the ones back in the day) are pretty well made, and some even come with a lifetime "never need to be changed" warranty. But the reason its a good idea is that if the old wires have any cracks in the insullation, or if they've even just worn thin in a spot or two, your spark will arc out onto the engine block and may cause poor burn in the chamber or even an out-and-out misfire condition. It's up to you, but for me I change the plug wires every 60,000 miles or so in all of my cars.


I may not be the sharpest crayon in the box, but at least I'm a pretty color

Just a short comment to what J D said -

With the least amount of daylight, raise the hood with

the engine running.

In darkness you can readily see what J D was talking

about.