Spark plugs ignite the fuel in a gasoline engine. Worn plugs cause rough running and poor economy.
In this article
- Intervals
- Symptoms
- Doing it
Intervals
Iridium and platinum plugs can last 60,000 to 100,000 miles. Copper plugs last about 30,000 miles.
| Plug type | Typical life | Notes |
|---|---|---|
| Copper | 20,000 to 40,000 mi | Cheap, short life |
| Platinum | 60,000 to 80,000 mi | Longer life |
| Iridium | 80,000 to 120,000 mi | Common now |
| Double platinum | 100,000 mi | Waste-spark systems |
Intervals and costs are typical ranges. Your owner’s manual comes first.
Symptoms
Rough idle, hesitation, poor fuel economy and trouble starting. A misfire code often points to a plug or coil.
A small spark does a lot of work.
Doing it
On many four-cylinder engines it is an easy job. On some turbo and V6 engines, access is awkward, and a shop may be a better option.
Do it in this order
- Check the interval in the manual
- Use the exact plug specified
- Torque to specification
- Replace the whole set
Practical tip
Use the torque value in the manual. Over-tightening can crack the plug or strip the threads.
Bottom line
Replace spark plugs on schedule, and use exactly the type specified.
Specifications, prices and rules change. Confirm current details with the manufacturer or the relevant authority before you buy or repair.
