📈 Average 2026 US Cost
$300 - $1,500
Most US drivers pay $500-$1,000 (full set) for this repair on a typical vehicle.
📈 What Affects The Price
- Plug type: Iridium plugs $8-$25 each. Platinum $5-$15. Copper $3-$8 (short-life only).
- Coil-on-plug vs distributor: COP coils $30-$120 each x4-8 cylinders. Distributor cars use one coil ($30-$80).
- Number of cylinders: I4 = 4 plugs + 4 coils. V6 = 6 of each. V8 = 8 of each.
- Engine access: V8 trucks easy. Transverse V6 rear bank may need intake removal.
- DIY vs shop: Plugs are one of the most DIY-friendly jobs.
- Boots and dielectric grease: Always replace boots if cracked; dielectric grease is essential.
💵 Cost Breakdown: Parts vs Labor
🛠️ Parts
$60 - $800
Full plug + coil set: I4 $80-$250. V6 $150-$450. V8 $200-$800.
👨🔧 Labor
$120 - $600
I4 1 hour. V6/V8 1.5-3 hours. Under-intake jobs add 1-2 hours.
🚗 Cost By Vehicle Class
| Vehicle Class | Typical Range | Notes |
|---|
| Compact car I4 | $200 - $450 | Easy COP swap |
| Sedan I4 | $250 - $550 | Coil-on-plug standard |
| SUV / Sedan V6 | $450 - $900 | Rear bank can be tight |
| Truck V8 | $550 - $1,100 | Easy access, more parts |
| Luxury / European V8 | $800 - $1,800 | OEM coils required, dealer pricing |
⚖️ DIY vs Shop
🔧 DIY
- +I4 plugs and coils in 1 hour
- +Massive labor savings
- +Big drivability improvement
- -Wrong torque cracks plug or strips threads
- -Anti-seize use is debated - check manual
- -Misfires can persist if injectors or compression are the real issue
🏭 Shop
- +Verifies misfire cause first (compression test)
- +Has a torque wrench and the right plugs
- +Resets ECU and confirms fix
- -Steep markup on a basic job
- -Dealers charge OEM-only at premium pricing
🔒 How To Avoid Overpaying
- Get a free code read first - P0301-P0306 tells you the cylinder.
- Replace plugs and coils as a set - mixing old and new will throw repeat misfires.
- Use NGK, Denso, or Bosch OEM-spec plugs. Skip eBay no-names.
- Add dielectric grease to coil boots - prevents arcing and moisture damage.
- Iridium plugs go 80-100k miles; copper plugs 20-30k.
- On V6/V8, do all coils together - the labor is the same and the others are the same age.
- Independent shops are 30-50% cheaper than dealers for ignition work.
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💬 Frequently Asked Questions
Should I replace just one coil or all of them?
If only one is misfiring and the others are recent, just one is fine. If all your coils are original and over 80k miles, do them as a set.
How often should plugs be replaced?
Iridium 80,000-100,000 miles. Platinum 60,000-80,000. Copper 20,000-30,000. Always check the owner manual for the exact spec.
What does dielectric grease do?
It seals the coil boot to the plug, preventing moisture and reducing arcing. A thin coat inside each boot is standard.
Will replacing plugs fix my misfire?
Sometimes - if the plug is fouled or worn. If a coil is bad, fuel injector is leaking, or compression is low, plugs alone will not fix it.
Is OEM worth it for coils?
Often yes. NGK, Denso, Delphi, Bosch OEM-equivalent coils are accurate. Aftermarket no-name coils have a high failure rate.