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Spark plugs/wires

My 2003 Buick Century has 65000 mi on it, but is 14.5 y/o, so I’m wondering - to err on side of caution - whether I should change the plugs/wires - to avoid misfires and improve performance?

Let sleeping dogs lie.

If there were a problem the plugs/wires, the Check Engine light would be on with a misfire code.

And if it were a severe miss, it would be flashing.


Yes, most definitely!

Is the rubber insulation cracked? If so, replacement I should a good idea. Replace one at a time so that you put both ends where they belong.

No, they use silicone rubber instead of natural rubber, they will last a long time. When you change plugs, be sure to use some silicone grease on the boots.

Probably but use only OEM or high grade wires. I developed a slight hesitation on load in my Pontiac at about 60,000 that was a bad wire. Then needed them again when they replaced plugs at about 125,000 when they fell apart. I really never noticed any performance improvement though unless you need plugs now too, but changing them avoids diagnosing a problem later (if you get them on correctly that is).

Thank you for swift reply! I haven’t inspected the plugs, so cannot say if any insulation is cracked. I’ll be traveling 2500 miles over the course of a week’s time and wondered if it was preemptively advisable.

Thank you!
I hear you about OEM. So, you had just a single wire changed and they didn’t recommend all wires and plugs? Can I ask how much they charged?

Makes sense. If it ain’t broke (yet)…
In your experience, you haven’t seen them fail without a code or warning?
I’m leery because I had one go (without any warning or even hesitation) on a Dodge Durango at about 60k. It conked out. Thanks.


If there’s a problem with a plug wire/spark plug, it’ll cause a misfire.

And OBDII, which your vehicle has, detects for misfires and turns on the Check Engine Light.

My 97 Accord has the original secondary ignition components @ almost 200K.

And unless the Check Engine light comes on with a misfire code, I’m going to leave them alone.

Let sleeping dogs lie.


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No they didn’t replace just one wire but the whole set. I don’t remember the price but somewhere around $100 plus the diagnostic fee. I had no check engine light just a once in a while bump at highway speeds in high gear and accelerating.

I wouldn’t replace the wires, but I’d have already replaced the plugs were it my car. I’d worry that leaving them in too long they may get stuck from time and exposure to the high temperature and pressures in the cylinder head, and that might cause a big expense b/c the cylinder head threads might get damaged removing them. Probably won’t happen, but why risk it for the relatively minor expense of replacing spark plugs. While I was replacing the plugs I’d visually inspect the spark plug wires looking for signs of cracking etc.

so a bud asked me today, have you changed your serpentine belt? I said no, 03 185k miles, and the shop says it is still ok. He is like they should be replaced every 65k miles. Now at 180k I have had the plugs replaced twice, per 100k recommendation, changed front and rear differential fluids, and transfer case fluid, radiator fluid, Trans flush by me then pan drop and filter, never spark plug wires, got an o2 sensor in the trunk, have not gotten to that yet,

One can do a lot, one can do a little, it varies how it works out at the end of the day