*** Bad spark plugs have an impact on fuel economy, engine performance and engine longevity***
# of cylinders = # of spark plugs
Depending on driving habits and environmental conditions, along with the type of vehicle, spark plugs will generally last between 30,000-80,000 miles. (Check owners manual for specifications) Another term used to replacing old spark plugs is a tune-up which sometimes will include other service such as topping fluids and basic inspection depending on the auto repair shop you go to.
What to watch for if spark plugs need replacing:
- Ignition problems
- Hesitation
- Lower gas mileage
- Misfires (which could also be many other issues)
For a general idea of what spark plugs look like when they are old compared to new see the images below.
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| Old and used spark plugs |
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| New spark plugs |
