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WRX Spark plugs

Your WRX

Pick your year to see what fits.

This page covers the WRX and STI. The non-turbo Impreza has its own page.

Restores lost power
Hard$50–$1502–3 hrs
All WRX mods

Why do it

Worn plugs cost power and throttle response, and turbo cars are hard on them. Fresh plugs bring back the punch.

Tools you'll need

Starting out? See our budget tool list.

Parts to buy

Double-check fitment before buying. We may earn a commission when you buy through these links, at no extra cost to you.

Before you start

  • Work on a cold engine. Do one plug at a time so nothing gets mixed up.
  • Thread each new plug in by hand first.
  • Work on a cold engine. The tight spot is the driver's side, so take your time there.
  • Torque specs from the video: plugs 12.9 ft-lb, coil bolts 6.3 ft-lb.
  • Work on a cold engine. There's little room, so a thin wall socket and short extensions help.
  • Work on a cold engine. Cylinder 2 is the hardest one, so go slow.

Steps

  1. Remove the battery

    • Disconnect the negative terminal, undo the battery bracket and lift the battery out for room on the driver's side.
    Watch this step (1A Auto, on a 2004 WRX) (0:24–3:05)

  2. Move the washer bottle and pull the first coil

    • Spray the bolts with penetrant, lift the washer bottle up, then remove the coil bolt and pull the coil.
    Watch this step (3:05–7:19)

  3. Swap the front driver's side plug

    • Loosen the old plug with the 5/8" socket and thread it out. Start the new one by hand, then tighten it down.
    Watch this step (7:19–10:39)

  4. Refit the coil and do the rear plug

    • Install the coil, then repeat for the rear plug on that side.
    Watch this step (10:39–14:40)

  5. Remove the intake parts on the passenger side

    • Undo the two 10mm air duct bolts, unclip the air box cover and move it aside.
    Watch this step (14:40–17:40)

  6. Swap the passenger side plugs

    • Free the harness, unplug the coil, then change each plug with the same socket and refit the coils.
    Watch this step (17:40–24:10)

  7. Put it all back

    • Refit the air box, washer hose, bolts and battery.
    Watch this step (28:53–33:40)

  8. Remove the battery

    • Disconnect the battery and lift it out.
    Watch this step (Blake's Garage, 2008-2014 WRX/STI) (0:43–2:04)

  9. Remove the air pump

    • Unbolt the air pump and move it out of the way.
    Watch this step (2:04–4:42)

  10. Swap the driver's side plugs

    • Pull each coil, swap the plug, and refit the coil.
    Watch this step (4:42–10:00)

  11. Refit the air pump

    • Bolt the pump and hoses back in.
    Watch this step (10:00–12:55)

  12. Remove the air intake

    • Take out the intake parts for room on the passenger side.
    Watch this step (12:55–13:58)

  13. Swap the passenger side plugs

    • Do both plugs the same way.
    Watch this step (13:58–15:33)

  14. Finish up

    • Refit the intake and battery, then start the car.
    Watch this step (15:33–16:17)

  15. Get the right socket ready

    • Check your socket fits the plug and check the gap on the new plugs.
    Watch this step (Alexs WReX, on a 2015-2021 WRX) (0:38–1:40)

  16. Swap the driver's side plugs

    • Remove the coils, swap the plugs and refit everything.
    Watch this step (1:40–2:51)

  17. Torque the plugs

    • Tighten the plugs to 12.9 ft-lb and the coil bolts to 6.3 ft-lb.
    Watch this step (2:51–3:24)

  18. Swap the passenger side plugs

    • Repeat on the passenger side.
    Watch this step (3:24–4:49)

  19. Get your tools ready

    • Lay out the socket and extensions you'll need.
    Watch this step (STiAlan, on a WRX STI) (0:49–1:35)

  20. Swap plugs on cylinders 2 and 4

    • Make room, pull the coils and change both plugs on this side.
    Watch this step (1:35–9:53)

  21. Swap plugs on cylinders 1 and 3

    • Do the same on the other side, then refit everything you moved.
    Watch this step (9:53–13:58)

  22. Prepare and get access

    • Clear the parts in the way so you can reach the coils.
    Watch this step (RZ1 Performance, on a 2022+ WRX) (0:00–2:28)

  23. Take apart the driver's side

    • Move what's blocking the coils on the driver's side.
    Watch this step (2:28–5:52)

  24. Swap the first driver's side plug

    • Pull the coil, swap the plug and refit the coil.
    Watch this step (5:52–9:37)

  25. Swap cylinder 2

    • This one is tight. Use the extension and swivel.
    Watch this step (9:37–13:08)

  26. Put the driver's side back

    • Refit everything you removed, in reverse order.
    Watch this step (13:08–15:19)

  27. Do the passenger side

    • Swap the passenger side plugs and start the car.
    Watch this step (15:19–18:30)

How to know it worked

Did this guide work for you?

Safety first

  • Park on flat ground, set the parking brake and chock the wheels.
  • Never get under a car held up only by a jack. Use jack stands.
  • Let the engine and exhaust cool first.
  • Disconnect the battery before unplugging electrical parts.
  • Wear safety glasses.
  • If something doesn't match your car, stop and ask a shop.

Follow your part's instructions and your service manual's torque specs.