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Q: When Should Engine Spark Plugs Be Replaced?

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When should engine spark plugs be replaced?

A: Regularly scheduled spark plug replacement ...

Regularly scheduled spark plug replacement should follow the prescribed manufacturer’s recommendations listed in your owner's manual.

With today’s advanced ignition systems and use of exotic materials, spark plugs can live for about 100,000 miles before requiring replacement.

Other reasons to replace your spark plugs would include:

  • Repair of engine misfire issues
  • Worn plugs due to high mileage, long-term storage, or engine performance malfunctions
  • Poor fuel economy
  • Emissions test failures

This is not a comprehensive list by any means.

Spark plugs are vital to the proper operation of your engine. I have personally worked on several vehicles that had close to 250,000 miles on them before coming into the shop for repair. All of the ignition system components (spark plugs, plug wires, ignition coil, distributor cap and rotor) were original to the vehicle and they too had nearly 250,000 miles of wear on them. Needless to say, with the amount of neglect these vehicles showed, the engines were totally worn out and had to be replaced.

Replacing your spark plugs when necessary will help keep your engine running well, get the most mileage from every tank of fuel, and keep those pesky emissions at their lowest levels. Should you need any help with replacing your spark plugs, contact a professional mechanic who can service your vehicle at your convenience.

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